TAZBTXDLAIR, SYNOPSIS OF CLASS E S, OB DEES, -AJSTID SUB-OEDEES. 



CLA8SE^ANlTgIIB : CLA88ES. 



Classes and Sub-classes. 



I. Cephalopoda 



II. Pteropoda ... 



III. Gasteropoda : 



Prosobrancliiata. 



Opisthobranchiata. 



Pulmonata. 



IV. Scapliopoda 



V. Pelecypoda , ... 



VI. Bractiiopoda 



II. 



VI 



Head. 



Large 



More or less distinct . 

 Distinct 



Rudimentary 

 None 



None 



Orders and Sub-Orders. 



III. 



a 



■§.a 



2 « 



I ■< 



o , <§ 



O 



Dibranchiata : 



Octopoda... 

 Decapoda 



Tetrabranchiata 



Thecosomata 



Gymnosomata ... 



Pectinobranchiata 



Scutibranchiata 



Podopthalma 

 Edriopthalma 



Polyplacophora. . . 



Nucleobranchiata 

 f Tectibrancliiata 

 J Nudibranchiata 



s 

 Pn 



IV. ... 



v. -i 



{ 



Anthobrancliiata 

 L Aiolobranchiata .. 



f Stylomatophora 



Monotremata ... 



Ditremata 

 Basom matophora 



Gehrydroptula ... 



Hygrophila 



Thalassophila ... 

 Soaphopoda ... 

 Sipbonida 



Sinupalliata 



Integripalliata ... 

 Asipbonida 



Homomyaria ... 



Heteromyaria ... 



Monomyaria 



Arthropomata 



Lyopomata 



Body. 



Often massive, enclosed 



in sack-like mantle ... 



Snail-like 



Worm like 



Enclosed in a mantle ... 



Inconspicuous, with two 

 coiled ciliated worm- 

 like arms 



Eyes. 



■ Sessile or pedunculate.. 



None ... 



Stalked or sessile 



None 



None or rudimentary. 



-None 



Mouth furnished with 



Two horny beaks., 

 Lingual armature.. 



Thread-like tentacles 

 Four fleshy leaflets 



Long filaments 



Respiration by means of 



Plume-like gills 



Branchiae external, or internal 

 Gills or branchiae 



Branchiae (2) 



Gills only 



Mantle lobes, no branchiae 



Locomotion effected by 



Tentacular arms 



Two lateral swimming discs 

 Creeping foot or disc 



A foot when not atrophied . . . 



Cilliae, when young; fixed in 

 the adult. 



ORDERS AND SUB-ORDERS- 



Distinguishing Characters. 



Gills, a single pair. 



M ti ; arms eight 



ii ii ; arms, ten 



ii two pairs 



ii within mantle cavity ; has an external shell 



ii indistinct; naked, no shell 



" in front of the heart ; shell spiral 



i> ii ii ii ii ii without anterior canal 



ii behind the heart 



II IT ti 



ii ii multivalve, 8 separate pieces 



ii pelagic animals, swimming by means of fin-like lobes 

 protected by a fold of the mantle 

 exposed or contractile into cavities in mantle ... 

 ii ii ii plumose, arranged round the anus 



ii ii ii various, not arranged 



Terrestrial, four tentacles ; eyes at the end of superior pair of tentacles 

 Orifices of sexual organs united n i'i m ,, m \\ 



ii ii 'i widely separated n ,, „ 



Eyes at the base of the tentacles, which are flattened and triangular ... 

 ii ii ii ii ; terrestrial; teguments rugose 



ii ii ii n ; fresh water ; n smooth 



ii ii ii ii ; sea shores and brackish water 



Shell open at both ends; straight or curved tube, not spiral ... 

 Having two well-developed muscular impressions 

 Siphon long ; pallial impression with a sinus... 



ii short ii n simple, without sinus 



No siphons ; pallial impression without a sinus 

 Muscular impressions ; two equally distinct ... 



ii ii H anterior small, posterior lar| 



'i ii one posterior... 



Shell usually articulated with hinge teeth ; arms generally supported by an internal shelly process 



Shell not u sually articu lated with h inge teeth ; arms free, not supported by an internal shelly process 



head a flattened disc 



Shell. 



Internal. 



Internal, external, or absent. 

 Mostly univalve, spiral, or conical. 



Straight or curved tube. 

 Bivalve hinged. 



Bivalve with perforated beak. 



(Fam. 



l. 



iii. 

 vi. 



vn. 



xl. 



xl. 



xlix. 



Iii. 



Jvm. 

 lviii. 



lxiv. 



Ixvi. 



lxix. 



lxix. 



lxxxi. 

 il xc. 

 II xc. 

 H xciv. 

 ii xcvii. 

 ii 



ii 



n. 



V. 



1. 



xlviii. 

 1. 

 Ii. 



Ivii. 



Ixiii. 

 lxiii. 



lxviii. 

 lxiv. 



lxv. 



Ixvii. 



lxviii. 



lxxxix. 



lxxx. 



lxxxix. 



ci. 

 xciii. 

 xcvi. 



ci. 



cii. 



