578 



HISTORY OF SYSTEMS. 



Jirrbinuvel. 



MUUTCIDJB 



S.Cassime 



TUKB1SEIIIIIE 



5 Jhjuccinin.ee. Op-'Fusinaz 5. 



Scolyminicl 



Elfurnince. 3 



The divisions of the PHYTOPHAGA are 1, the Helicidaa ; 

 2, the Trochidae ; 3, the Heliotidae ; 4, the Naticidae ; and 

 5, the Turbidae. Their analogies with the Zoophaga are 

 thus illustrated : 



Families of the 

 Phytophaga. 



Analogical Characters. 



HELICID^S. 

 TROCHID^E. 



HALIOTID^E. 



Typical. 

 Sub-typical. 



Families of the 



Zoophaga. 

 MURICID.K. 

 TURBINELLID.E. 



(Foot enormously large; tentacular 

 very short; spire of the shelH VOLUTID^E. 

 ver small. ) 



NATICID.E. 





very small. 



Shell highly polished, partly 01 

 { entirely covered by the mantle. 



(Animal carnivorous ; mouth pro-"| 

 bosciform, with a respiratory >' 

 siphon. J 



The order DITHYRA is thus subdivided: 1, the MACRO- 

 TRACHIA, where there are either one or two siphons ; 2, the 

 ATRACHIA, having none ; 3, the TUBULIBRANCHIA, or tubular 

 shell-fish, having an indistinct head, and an operculum to 

 their shell ; 4, the CHELIOSOMID.E, with a cartilaginous 

 covering and two orifices ; and 5, the BRACHIOPODA, or 

 anomian bivalves. The whole of these have their prototypes 

 in the Gasteropoda, as is shown in this table : 



Tribe* of the 

 Dithyra. 



MACROTRACHIA. 



ATRACHIA. 

 BRACHIOPODA. 



A nalogies. 

 f Animal with the mantle formed into' 



Tribes of the 

 Gasteropoda. 



^ an elongated siphon, simple or V ZOOPHAGA. 

 [ double. J 



Mantle free, and without a siphon. PHYTOPHAGA. 



{ R Top P oda ally repreSenting the Cepha "} TEOTIBEANOHIA. 



