112 



MOLLUSCA 



TABULAR VIEW OF THE SUBDIVISIONS OF THE CLASS GASTROPODA, ARRANGED so AS TO SHOW THEIR SUPPOSED GENETIC 



RELATIONSHIPS. 



Class. GASTROPODA. 



(Archisopleurum. ) 



Sub-class 1. ISOPLEURA. 



Sub-class 2. ANISOPLEURA. 

 (ArchwutJiyneurum. ) 



%. Si 



Branch a. STREPTONEURA. 

 (Archizygobranchium. ) 



Branch b. EUTHYNEURA. 

 (Archiopisthobranchium. ) 



Order 1. ZYGOBRANCHIA. 



Order 2. AZYQOBRANCHIA. 

 (Archiholochlamydum. ) 



Order 1. OPISTHOBRANCHIA. 

 (Archipalliatum. ) 



Order 2. PULMONATA. 



(Archibasommatum . ) 



Sect. a. 

 Heptardia. 



Sect. 6. 

 Natantia. 



Sect. a. 

 Palliata. 



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1 1 



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 I I 



Sect. 6. 

 Non-Palliata. 



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 I 



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Family 11. Naticidse. 



Genera : Natica, Lam. ; Sigaretus, Lam. ; Neritopsis, Gratel. 

 Family 12. Entoconchidie. 



The single genus and species Entoconcha mirabilis, discovered by 

 Joh. Miiller in 1851, parasitic in Synapta digitata. The adult 

 form is not known. 

 Family 13. Marsenidse. 



Genera : Marsenia, Leaeh ; Onchidiopsis, Beck. 

 Family 14. Acirueidee. 

 Genera : Acmsea, Eschsch. ; Lottia, Gr. ; (probably these will be 



found to belong to the Zygobranchia). 

 Family 15. Capwlidas. 

 Genera : Capulus, Montf. ; Calyptram, Lam. (fig. 40) ; Trochita, 



Schum. 

 Family 16. Littorinidse. 



Genera : Littorina (the Periwinkles, fig. 46) ; Modulus, Gray ; 

 Lacuna, Turt. ; Rissoa, Frein. ; Hydrobia, Hartm. ; Assiminia, 

 Leach. 



Family 17. Palvdinidss. 

 Genera : Paludvna (River-Snail) (figs. 7, 21) ; Bithynia, Gray ; 



Tanalia, Gray. 

 Family 18. Valvatidse. 



Genus : Valvata (fig. 45), fresh-water. 

 Family 19. Ampullaridee. 



Genus : Ampidlaria (can breathe air by means of the walls of 

 the pallial chamber as well as water by the gill ; fresh-waters 

 of tropical America, Africa, and East Indies). 



Sub-order 2. Pneumonechlamyda. 



Characters. Pallial chamber a lung-sac; no gill; mouth on a 

 rostrum, not a retractile proboscis ; terrestrial habit. 



Family 20. Cydostcmiidse. 



Genera : Cyclostoma, Lam. ; Cyclophorus, Montf. ; Ferussina, 



Gratel. ; Pupina, Vignard. 

 Family 21. Hclicinides (radula rhipidoglossate rather than tsenio- 



glossate). 

 Genera : Stoastoma, Adams ; Trochatella, Swains. ; Helicina, 



Lam. ; Proserpina, Guild. 

 Family 22. Aciculidse. 

 Genera: Acicula, Hartm.; Oeomelania, Pfr. 



Sub-order 3. Siphonochlamyda. 



Characters. Reptant Azygobranchia with the margin of the 

 mantle drawn out to form a trough-like siphon which notches the 

 lip of the shell ; shell always spiral ; usually an operculum, horny 

 or lamelliform ; either a rostrum or a retractile proboscis ; exclusively 

 marine ; mostly carnivorous. 



* Teenioglossa (3.1.8). 

 Family 1. Slrombidse. 



Genera : Stromlnts, L. ; Ptcroccras, Lam. ; Eostellaria., Lam. 



(fig. 43). 

 Family 2. Aporrhaid/e. 



Genus : Aporrhais, Da Costa. 

 Family 3. Pcdicularidas. 



Genus : Pcdicularia, Swains. 

 Family 4. Dolidse. 



Genera : Cassis, Lam. ; Cassidaria, Lam. ; Dolivm, Lam. ; Ficula, 



Swains. 

 Family 5. Tritonidse. 



Genera : Trttonium, Cuv. (fig. 42) ; Ranclla, Lam. 

 Family 6. Cyprssidas (the Cowries). 



Genera : Cyprsea, L. ; Ovuhim, Brag. (fig. 41) ; Erato, Risso. 



*Toxiglossa (1.0.1). 

 Family 7. Conidee. 

 Genus : Conus, L. 

 Family 8. Terebridai. 



Genus : Tercbra, Adans. 

 Family 9. Pleurotomidee. 



Genus : Pleurotoma, Lam. 

 Family 10. Cancellaridas. 

 Genus : Cancellaria, Lam. 



*Rachiylossa (1.1.1 or .1.). 

 Family 11. Muricidas. 



Genera : Murex, L. ; Trophon, Montf. ; Fusus, Brug. ; Pyrula, 



Lam. (fig. 38) ; Turbinclla, Lam. 

 Family 12. Bucdnidee. 



Genera : Buccinum, L. ; Nassa, Lam. (fig. 5) ; Purpura, Brug. 



(fig. 47) ; Concholepas, Lam. ; Magilus, Montf. 

 Family 13. Mitridse. 

 Genus : Mitra, Lam. 



