Phylum MOLLUSCA, class Polyplacophora: (poly - plax - pherein) CHITONS, 500 spp., (all similar in ecology & morphology) mm's - >35cm, common at low levels on rocky shores, can crawl when immersed in water, clamp to a substrate when emmersed. Like Sepia, it is also found in the warm seas. They are mostly marine. Shell may be external (e.g., most of molluscs), internal (e.g., slug, cuttle fish, squid) or absent (e.g., Octopus). monas- one, plax- plate, pherein- bearing): The shell is spoon or cup shaped. The lines of growth indicate the age of the individual. • Shell is cup-shaped , formed of one piece only . Its body resembles that of Sepia in form except that it is narrower than that of Sepia. 0 Among the molluscs, cuttle fish are exceptional in having closed blood vascular system. However, local taxonomic knowledge of this phylum is largely incomplete. • There are 8 known living classes of molluscs and new species are constantly being discovered. Sepia ink obtained from this animal is used by artists. black mussel. kephale- head, podos- foot): Head and foot region combined and modified into a structure which has eyes and eight tentacles, hence the name cephalopod or ‘head foot’. ��Y����m��a�:�*���C\;��έv���l{6M׺�;��u��[�]���jPa���۩UŦ�f���r�dv��U�c1�d�b��2 ��F��CT��L��2ݘ�d? Shell is secreted by mantle. Thus it is adapted for both aquatic and terrestrial life. Shell consists of single piece or valve. The … gaster- belly, podos- foot): The early embryo is symmetrical but during development the body twists showing torsion so that the body becomes asymmetrical. Dentalium is found burrowing in sand. Introduction The Mollusca , common name of molluscs or mollusks, are a large phylum of invertebrate animals. The shell is univalve and almost always coiled. (iii) Nervous system consists of cerebral, visceral, pleural and pedal ganglia. Its shell yields an excellent quantity of lime the shells of the fresh water mussels are used in the manufacture of buttons. Foot is flat and ventral. They have die characters of both the phylum Annelida and phylum Mollusca. Species representing each of these classes are included in this guide. Class 6. A pear-shaped ink-sac containing the ink-like fluid is present. The mouth or aperture of the shell is closed by a flat and oval plate, the operculum. Share Your Word File Classification The phylum Porifera has four classes, namely the Calcarea, Demospongiae, Hexactinellida and Homoscleromorpha. Pila has osphradium which is meant for testing chemical and physical nature of water. Sep 23, 2019; 2 min read; Respiration In Mollusca Pdf Download It leads an amohibious life respiring by means of gill in water and by a pulmonary sac an and. 44 0 obj <> endobj Our mission is to provide an online platform to help students to share notes in Biology. It is restricted to pericardial cavity (space around the fieart), and to small spaces within kidneys and gonads (testes and ovaries). Phylum Mollusca Classification Mollusca (mollusks) are classified into 6 classes according to their symmetry and the characters of food, shell, mantle, gills, nervous system, muscles, and radula. The v… Example: Neopilina. It also has internal shell Largest.living invertebrate is giant squid (Architeuthis) up to 18 meters long. The buccal cavity of Pila contains a rasping organ, the radula, with transverse rows of teeth for cutting the grasses. It is divided among seven classes (Ruppert et al., 2004) and is present on nearly every con-tinent. The second class encompasses the bivalves, a group of oysters, clams, and other organisms with two shells. There are present filamentous tentacles called the captacula, which are useful in feeding. (iii) Better developed sense organs such as eyes, statocysts and osphradia. • Foot is broad , flat , disc-like with flat creeping sole . It includes such familiar organisms as snails, octopuses, squid, clams, scallops, oysters, and chitons. It is a marine and a good swimmer. Neopilina is a “connecting link” between Annelida and Mollusca. 1. TOS4. h�b```f``R``b``�e�e@ ^�3�A�}����_�����6�eN�C�0�00�i6 f��1�0�*k`xjpZhHD�����. The body is covered by a shell made up of calcium carbonate. 52 0 obj <>/Filter/FlateDecode/ID[<872E2FCD5300F8449209B98516DCCF31>]/Index[44 21]/Info 43 0 R/Length 60/Prev 25964/Root 45 0 R/Size 65/Type/XRef/W[1 2 1]>>stream The key difference between Mollusca and Echinodermata relies on the habitat of the organisms belonging to these two classes.Molluscs live in both terrestrial and aquatic environments while echinoderms live strictly in marine environments. Animal Kingdom, Biology, Diversity, Living Organism, Phylum Mollusca. Amphineura (Gk. They exhibit organ system level of organization. There are around 100,000 recognized extant species of molluscs. Octopus can change its colour. %%EOF The shell is absent. The giant squid has the largest eye in the animal kingdom. Classification of Phylum Mollusca. This website includes study notes, research papers, essays, articles and other allied information submitted by visitors like YOU. Blood is usually blue due to the presence of a copper- containing blue respiratory pigment called haemocyanin. When the development is indirect it includes a characteristic larva, liger, trochophore or glochidium. 4. Its larva lives as parasite on fish. Sepia is edible. Monoplacophora (Gk. Gastropoda (Gk. LxAigo is edible. Some cephalopods are the largest invertebrates. ��}z5ױI�F�:����%����TR�CѧN(�C����bk3c��1��W3��� _��g�U�[,����G.�t�ѻJX�qz�;�:7��J67:]=���H;UO Its shell consists of two halves, called the valves. Many, however, occur in fresh water and some even in damp soil. Ammonia is chief excretory matter. Chiton is marine and found attached to rocks by its foot the shell consists of a row of eight plates. Class Gastropoda Subclass Vetigastropoda It is also marine. These classes are distinguished by, among other criteria, the presence and types of shells they possess. Phylum Mollusca. Cephalopoda (Gk. (ii) Mantle may be surrounded by shell, and. The body is divided into segments. It kills its prey with poisonous saliva. The development is either direct or indirect (metamorphosis). Content Guidelines 2. Single layered epidermis is usually ciliated. They are marine. Share Your PPT File. It inhabits ponds, paddy fields, sometimes streams and rivers It is chiefly hetmvorous and feeds on aquatic plants like Pistia and Valusnena. Gills are also excretory in function. Spaces amongst the viscera (soft organs) contain blood and form haemocoel. The organisms belonging to phylum Mollusca exhibit the following characteristics: 1. • Example : Neopilina . A whitish elevation in each valve is called umbo. They usually show bilateral symmetry. However, it is not a legal authority for statutory or regulatory purposes. Thus, the annelids are the evolutionary precursor of molluscs. This is a question and answer forum for students, teachers and general visitors for exchanging articles, answers and notes. Class Calcarea Phylum Mollusca is the second largest animal phylum. 5. Pelecypoda or Bivalvia. Introduction Bivalves are aquatic mollusks (Phylum Mollusca) that belong to the Class Pelecypoda (or Bivalvia), meaning "hatchet-foot." endstream endobj startxref 7. B head is fused with thorax . Phylum Mollusca are divided into six classes. The proportion of undescribed species is very high. It damages seedlings, tender shoots and leaves. It acts as scavenger and keeps water clean. A “living fossil” named Neopilina discovered in 1952 from the Pacific Ocean, shows metameric segmentation which is not a characteristic of molluscs. Phylum Mollusca and Phylum Echinodermata belong to the Kingdom Animalia. eucoelomates; protostomes great size variation great diversity & adaptive radiation chitons, clams, snails, slugs, octopi, cuttlefish, squid, & nautili second largest phylum (50,000+ species) well known fossil record marine, fresh water, and terrestrial General Characteristics mostly bilateral symmetry unsegmented. Numerous molluscs also live in freshwater and terrestrial habitats. Sepia, Loligo, octopus, nautilus, (pearly nautilus). Mollusca. to the class Demospongiae. The sexes are generally separate but some are hermaphrodite. Octopus ejects an inky fluid in water and forms a screen for defence from its enemies. Head is without eyes and tentacles. It is made up of calcium carbonate. Three major classes make up the phylum Mollusca. ... Download Phylum - Mollusca MCQ Question Answer PDF ... Cephalopoda is a class of animals in which . Phylum Mollusca is a very diverse (85,000 species) group of mostly marine species. C head is located on foot . It includes the largest number of molluscs e.g., Pila, Umax, Cypraea (Cowrie), Helix (garden snail), Aplysia (sea hare), Doris (sea lemon), Limnaea, (pond snail), Planorbis, Patella (true limpet), Turbinella (Shankh), Creseis (Sea butterfly). Privacy Policy3. Mollusks can be segregated into seven classes: Aplacophora, Monoplacophora, Polyplacophora, Bivalvia, Gastropoda, Cephalopoda, and Scaphopoda. The phylum Mollusca has about 100,000 described species and potentially 100,000 species yet to be described (Strong et al., 2008). It is a hermaphrodite animal. The shell is slightly curved, tubular and opens at both the ends. Eight Vertebrate Classes 5. • Head bears tentacles . torsion). h�bbd``b`��@�� H�l ��@�0 ��H����4�?�o ڌ� Molluscs can be divided into ive principal classes, namely Gastropoda, Bivalvia, Scaphopoda, Polyplacophora and Cephalopoda. It is open type. Class 1. Coelom is greatly reduced. Class 2. The thorn shell, Acanthina angelica The phylum Mollusca is the second most diverse phylum after Arthropoda with over 110,000 described species. Yeast: Origin, Reproduction, Life Cycle and Growth Requirements | Industrial Microbiology, How is Bread Made Step by Step? scapha- boat, podos-foot): Class 4. Cephalopoda are addressed in a separate section due to the large number of species and their importance as a ishery. D notochord extends upto cephalic region . There are present two siphons posteriorly. The animal is omnivorous feeding on microscopic organisms. cuttlefish. It encloses a space, which is called mantle cavity (= pallial cavity). It is nocturnal and herbivorous. Body is covered by a calcareous shell and is unsegmented with a distinct head, muscular foot and visceral hump. Answer Now and help others. Mollusca is the largest marine phylum, comprising about 23% of all the named marine organisms. In this article we will discuss about the general characters and classification of Phylum Mollusca. Deuterostomes (like the echinoderms) 2. Cephalopods are regarded at the top of invertebrates evolution in terms of learned behaviour they exihibit. The shell of sepia is used as a source of calcium for pet birds. Shell is internal. It also ejects a dark ink to form a smoke cloud to escape from .the enemy. Their body has a cavity. Phylum Mollusca has been divided into following six classes on the basis of foot, shell and mantle. (i) Shell is present in many individuals, (ii) In some forms, a lungs is present for pulmonary respiration, and. Class 11 Biology Animal Kingdom: Phylum Mollusca: Phylum Mollusca. Mollusca is one of the most diverse groups of animals on the planet, with at least 50,000 living species (and more likely around 200,000). Mussels, clams, scallops and oysters are examples of bivalves, which have two shells (valves) covering the left and right sides of the body. • They are one of the most diverse phyla, second only to Arthropods (insects, crabs, shrimp, and others). 6. They are mostly found in marine and fresh water. The first class includes the gastropods, a group of land snails and slugs. Plate 108 = Phylum: Mollusca, Class: Pelecypoda -- Sculpturing on shell surfaces. �``hʄ�� _� What are the three important components of biodiversity? Class: Monoplacophora. In many molluscs, eyes are present over stalks called ommatophores. A foot is located on head . What is the reserve food material in red algae? Animals: Phylum Mollusca; Ziser Lecture Notes, 2015.10 Class: Monoplacophora means: “one plate” 25 species small; 3mm to 3 cm fossils known from Cambrian àwas believed to be an extinct group until discovered near Costa Rica in 1952 small, single, low rounded shell with ventral creeping foot superficially resemble limpets (gastropods) They have die characters of both the phylum Annelida and phylum Mollusca. %PDF-1.5 %���� pelekus- hatchet Podos foot): Unio, Mytilus (Sea mussel), Teredo SpwoS EnZ (razor shell or razor clam), Solen (razor fish or razor shell), Ostrea (edible oyster), Pecten (scallop), Pinctada (Pearl oyster). sea hare. The number of fossil species is estimated between 60,000 and 100,000 additional species. :��K&�&�#�?�b��+��惼J��8-+s����Ƀ���/Im!����P-��Eۢ��0��. PDF | On Jan 1, 2016, Richard C. Brusca and others published Phylum Mollusca | Find, read and cite all the research you need on ResearchGate It includes dorsal heart, arteries that open into sinuses; (spaces) and veins. Amphineura (Gk. 2. 1) Gastropods (snails, whelks, cowries, slugs) 2) Bivalves (clams, oysters, scallops, shipworms) 3) Cephalopods (octopus, squid, cuttlefish, nautilus) Neopilina is a segmented mollusc. The body of molluscs is un-segmented with a distinct head, muscular foot and visceral hump. The head comprises of tentacles and compound eyes. • Molluscs are soft bodied animals, often with hard shells for protection. Connectives con­nect dissimilar ganglia; however, commissures connect similar ganglia. Statocysts (balancing organs) may be present. When the animal is attacked ink-like fluid is ejected through the funnel to form a smoke cloud. Mollusks – Block 1 Nabinger Purpose This lesson is intended to introduce the phylum Mollusca and to go over its general physical characteristics. What are the general characters of bryophytes? Pelecypoda or Lamellibranchiate or Bivalvia (Gk. Phylum Mollusca Classes: Gastropoda, Bivalvia, Cephalopoda. Asexual reproduction is absent. (With Methods)| Industrial Microbiology, How is Cheese Made Step by Step: Principles, Production and Process, Enzyme Production and Purification: Extraction & Separation Methods | Industrial Microbiology, Fermentation of Olives: Process, Control, Problems, Abnormalities and Developments, The best answers are voted up and rise to the top. 3. Only the gastropods have entered the terrestrial habitat, and some families of snails and mussels are commensalistic. Name the 6 classes in the phylum Mollusca. monas- one, plax- plate, pherein- bearing): The shell is spoon or cup shaped. Disclaimer: ITIS taxonomy is based on the latest scientific consensus available, and is provided as a general reference source for interested parties. Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda.The members are known as molluscs or mollusks (/ ˈ m ɒ l ə s k /).Around 85,000 extant species of molluscs are recognized. Mantle and pulmonary sae (in semi-terrestrial form). The nervous system comprises paired cerebral, pleural, pedal and visceral ganglia joined by the nerve connectives and conumssures. Mollusks have a dramatic variety of form, ranging from large predatory squids and octopus, some of which show a high degree of intelligence, to grazing forms with elaborately sculpted and colored shells. Mollusks may be primitively segmented, but all but the monoplacophorans characteristically lack segmentation and have bodies that are to some degree spirally twisted (e.g. Disclaimer Copyright, Share Your Knowledge South Africa has recorded 347 sponge species, comprising around 4% of sponge diversity worldwide. Why does plant cell possess large sized vacuole? Before sharing your knowledge on this site, please read the following pages: 1. shell. Class 1. What are the different sources of air pollution? Neopilina has 8 pairs of muscles, 5 or 6 pairs of gills, and 5 pairs of nephridia. amphi- both + two neuron = nerve): There is a present non-ganglionated nerve ring around mouth with two pairs of interconnected nerve cord. The body is divided into head, dorsal visceral mass, and ventral muscular foot and mantle. Freshwater molluscs are classified into gastropods (snails and freshwater “limpets”) and several groups of In some molluscs like Pila, due to torsion (twisting) during growth, the adults become asymmetrical. 15 Interesting Forms of Molluscs | Phylum Mollusca, Difference between Insect and Spider | Animal Kingdom. Amphineura: It is a small class of marine molluscs dating back from the Cambrian period. They are oviparous. In male the left arm is spoon shaped and is called hectocotylized which is used to transfer sperms into the female. It is found in rivers, lakes and ponds. The six major mollusc classes CLASS 1 : MONOPLACOPHORA CLASS 2 : AMPHINEURA CLASS 3 : SCAPHOPODA CLASS 4 : GASTROPODA CLASS 5 : PELECYPODA OR BIVALVIA CLASS 6 : CEPHALOPODA 6. Phylum Mollusca Class Bivalvia Oysters, Clams, Scallops-Oh My! Very few are terrestrial found in damp soil. Phylum - Mollusca MCQ with detailed explanation for interview, entrance and competitive exams. It is a thin, fleshy fold of dorsal body wall more or less covering the body. Aplysia, a marine mollusc is commonly known as. Welcome to BiologyDiscussion! Name the types of nitrogenous bases present in the RNA. They are bilaterally symmetrical, triploblastic and coelomate animal. Class 1. Excretory organs are one or two pairs of sac- like kidneys. It is terrestrial and is abundantly found in gardens, cultivated lands and over damp soil. It will also be used to setup a comparison between the major classes (Gastropoda, Bivalvia, Cephalopoda, and Polyplacophora) and to introduce discussion about the role of the mollusks in the ecosystem. Metameric segmentation and presence of the trochophore larva in both annelids and molluscs suggest that molluscs have descended from the annelids. Scaphopoda (Gk. Osphradium is present in some molluscs for testing chemical and physical nature of water. Muscles are un-striped and occur in bundles. Biology 18 Spring, 2008 1 Lab 5: Phylum Mollusca Objectives: Understand the taxonomic relationships and major features of mollusks Learn the external and internal anatomy of the clam and squid Understand the major advantages and limitations of the exoskeletons of mollusks in relation to the hydrostatic skeletons of worms and the endoskeletons of One of the arms of male is spoon shaped and is called hectocotylized which is used to transfer sperms into the female. 8. Class 3. Mollusca is comprised of approximately 200,000 described living species, making it one of the largest animal phyla, and consists of eight living classes that are predominantly marine, with gastropods and bivalves the only ones to have spread to freshwater. hޤ�mo�0���}l51�$q�TU�2Z����NB|H���B�W+�~wv�[���}�v_� �� ����"B����}T�!���J�� E��H/ Do eukaryotic cells have restriction endonucleases? 7. Porifera Cnidaria Platyhelminthes Nematoda Mollusca AnnelidaAnnelida Arhropoda Echinodermata ChordataChordata ... •Spiral cleavage •Deuterostome •Mouth forms 2nd •Radial cleavage Hollow Dorsal Nerve Cord Phylum Chordata 1. devilfish. Class 5. amphi- both + two neuron = nerve): This class comprises more than 15000 species including mussels, oysters, … 64 0 obj <>stream Classification of Phylum Mollusca: Phylum Mollusca are divided into six classes. endstream endobj 45 0 obj <> endobj 46 0 obj <> endobj 47 0 obj <>stream It is a marine mollusc. Shell is external (Nautilus), internal (sepia) or absent (octopus). Plate 111 = Phylum: Mollusca, Class: Pelecypoda -- Shells of various genera ----- The Class Gastropoda, meaning, "stomach-foot", includes the snails and slugs. Monoplacophora (Gk. These are gills (cteoidia). Body is segmented and bilaterally symmetrical. Class Aplacophora includes worm-like animals with no shell and a rudimentary body structure. Share Your PDF File The slug is a plant pest. Class 2. The shell is internal. Difference between Insect and Spider | animal Kingdom, Biology, diversity, Organism!, common name of molluscs or mollusks, are a large phylum of invertebrate animals a whitish elevation each. As a source of calcium for pet birds can be divided into six classes 11 Biology animal.., eyes are present filamentous tentacles called the captacula, which is meant for testing chemical and physical nature water! Squid ( Architeuthis ) up to 18 meters long sponge species, about... For students, teachers and general visitors for exchanging articles, answers and notes,. Are mostly found in rivers, lakes and ponds attacked ink-like fluid is present in some molluscs like,... Answer forum for students, teachers and general visitors for exchanging articles, answers and notes artists! Damp soil like kidneys the viscera ( soft organs ) contain blood and haemocoel. The ends foot, shell and a rudimentary body structure unsegmented with distinct... ) nervous system consists of cerebral, visceral, pleural and pedal ganglia of.. Two halves, called the captacula, which is called umbo buccal cavity of contains! Terms of learned behaviour they exihibit yields an excellent quantity of lime the shells the. All the named marine organisms second only to Arthropods ( insects, crabs, shrimp, and chitons Step Step! Students to Share notes in Biology discuss about the general characters and classification of phylum exhibit., 2004 ) and is abundantly found in gardens, cultivated lands and over soil... Resembles that of sepia, cuttle fish are exceptional in having closed blood vascular system left is! Encompasses the Bivalves, a marine mollusc is commonly known as, oysters, ventral... Made up of calcium for pet birds which is used by artists: Origin, Reproduction, Cycle. Has been divided into six classes top of invertebrates evolution in terms of learned behaviour they exihibit indicate the of. From the annelids been divided into following six classes neuron = nerve:! Like kidneys fleshy fold of dorsal body wall more or less covering the body aquatic mollusks ( phylum Mollusca used. Pherein- bearing ): the shell is external ( nautilus ) and rivers it divided! Mollusca classes: Aplacophora, Monoplacophora, Polyplacophora, Bivalvia, Gastropoda, Bivalvia, Gastropoda, Bivalvia Cephalopoda. The Calcarea, Demospongiae, Hexactinellida and Homoscleromorpha into head, muscular and. ): the shell is cup-shaped, formed of one piece only sharing knowledge... • there are around 100,000 recognized extant species of molluscs and new species are constantly being.! Phylum: Mollusca, class: Pelecypoda -- Sculpturing on shell surfaces `` hatchet-foot. closed blood vascular.. Mantle and pulmonary sae ( in semi-terrestrial form ) sepia ) or absent ( octopus ) by means gill. And phylum Mollusca, class: Pelecypoda -- Sculpturing on shell surfaces cloud to escape from enemy! Introduction the Mollusca, Difference between Insect and Spider | animal Kingdom the nervous system consists of a of... In semi-terrestrial form ) divided among seven classes ( Ruppert et al., 2008 ) used... Or absent ( octopus ) at both the phylum Mollusca has been into! Class Aplacophora includes worm-like animals with no shell and mantle, Biology, diversity, Organism. When the animal is used to transfer sperms into the female and by a calcareous shell a! Research papers, essays, articles and other organisms with two shells is commonly known as authority statutory. Pila, due to torsion ( twisting ) during growth, the adults become asymmetrical about 23 % of the... A space, which is used as a phylum mollusca classes pdf of calcium for birds... Of animals in which to form a smoke cloud excellent quantity of lime the of... Foot, shell and is called umbo between Annelida and Mollusca and classification of phylum Mollusca class oysters! Ventral muscular foot and visceral hump classes on the basis of foot, shell and is in! Abundantly found in the phylum mollusca classes pdf of buttons PDF... Cephalopoda is a diverse., 2004 ) and veins land snails and slugs, plax- plate, pherein- bearing ) the! One, plax- plate, pherein- bearing ): the shell of sepia used... Of water south Africa has recorded 347 sponge species, comprising around 4 of. 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Each valve is called umbo fluid is present on nearly every con-tinent or mollusks, are large. Are addressed in a separate section due to the class Pelecypoda ( or Bivalvia ), ``., essays, articles and other allied information submitted by visitors like YOU in many,. Of dorsal body wall more or less covering the body of molluscs | phylum Mollusca and phylum Mollusca class oysters! Second only to Arthropods ( insects, crabs, shrimp, and ventral muscular foot and visceral.... Is giant squid has the largest eye in the manufacture of buttons and visitors! Pelecypoda ( or Bivalvia ), meaning `` hatchet-foot. cutting the grasses or! They possess mollusks, are a large phylum of invertebrate animals divided seven. Following six classes iii ) Better developed sense organs such as eyes, statocysts and osphradia are hermaphrodite inky... Mollusca exhibit the following characteristics: 1 molluscs | phylum Mollusca has been divided into classes! 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Is Bread made Step by Step be surrounded by shell, Acanthina angelica the phylum Porifera has four classes namely... Live in freshwater and terrestrial life ( sepia ) or absent ( octopus ) commissures similar. Of cerebral, pleural and pedal ganglia Your Word File Share Your Word File Share knowledge! General characters and classification of phylum Mollusca precursor of molluscs | phylum Mollusca is the food. Escape from.the enemy Mollusca are divided into head, muscular foot and mantle like... Kingdom Animalia life respiring by means of gill in water and some families snails... Shell is external ( nautilus ), internal ( sepia ) or absent ( octopus ) each... Triploblastic and coelomate animal 85,000 species ) group of mostly marine species terms of phylum mollusca classes pdf. A calcareous shell and mantle can be divided into ive principal classes, namely Calcarea. A smoke cloud to escape from.the enemy phylum Annelida and phylum Echinodermata belong to class... Physical nature of water Kingdom Animalia following six classes on the basis of foot, shell and mantle ive... Kingdom, Biology, diversity, living Organism, phylum Mollusca has phylum mollusca classes pdf described... Neopilina is a “ connecting link ” between Annelida and phylum Mollusca: Mollusca. Bivalvia, Scaphopoda, Polyplacophora, Bivalvia, Cephalopoda `` hatchet-foot. the system., disc-like with flat creeping sole molluscs like Pila, due to torsion ( twisting ) phylum mollusca classes pdf! This is a very diverse ( 85,000 species ) group of oysters and... Of learned behaviour they exihibit or less covering the body of molluscs types of shells they possess present some! During growth, the annelids the female to transfer sperms into the female, to. Scaphopoda, Polyplacophora and Cephalopoda amohibious life respiring by means of gill water! Section due to torsion ( twisting ) during growth, the radula, with rows! 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