400 



MOLLUSCA. 



Fam. 24. Chenopodidae (Aporrhaidae). Foot elongated, narrow; proboscis 

 short, tentacles long; siphon short. Shell like that of Klrombus. Chenopus 

 Philippi (Aporrhais Aldrovandus) . 



Fam. 25. Struthiolariidae. Shell buccinoid ; operculum claw-shaped, 

 notched ; foot broad and short. Struthiolaria Lam. 



Fam. 26. Cypraeidae. Cowries. Mantle reflected over the shell, and 

 provided with appendages ; shell convolute, enamelled ; spire concealed ; outer 

 lip thickened, inflected ; operculum absent. The young shell has a prominent 

 spire. Cypraea L. , Cowry ; Erato Hisso ; Ovida, Brug. ; Pustidaria Swainson. 



Fam. 27. Doliidae. Shell veutricose, spirally furrowed ; no operculum ; 

 eyes stalked; foot large and expanded; siphon long. Dolium Lam., the Tun: 

 Pyrula (Pirula) Lam., fig-shell. 



Fam. 28. Cassididae. Shell ventricose with varices, spire short, outer lip 

 reflected or thickened, operculum semilunar ; eyes sessile ; foot large, rounded in 

 front; proboscis and siphon long. Cassis Lam., helmet-shell (Fig. 314); 

 Cassidaria Lam. 



Fam. 29. Tritonidae. A proboscis ; siphon well developed but short ; foot 

 short; shell thick, varicose, outer lip inflected and thickened, operculum 

 corneous ; periostracum often thick and hairy. Triton Lam. ; Ranella Lam. 

 frog-shell. The genus Oocorys Fischer, is allied here. 



ff Ve 



e A 1 



Br 



Oc Te 



BG 



Bm 



FIG. 315. Male of Cari.ncn-iu mediterranea (after Souleyet, Gegenbaur, and Keferstein). A anus ; 

 A r anterior aorta ; At auricle ; BG buccal ganglion; Em buccal mass; Br gills ; CG cerebral 

 ganglion ; F flagellum ; L liver ; M crop ; Jl/g mantle ganglion ; N kidney ; mouth ; Oc 

 eye ; Ot otocyst ; p pro- and mesopodium ; PC penis ; Pg pedal ganglion ; S sucker ; Sp 

 salivary gland ; T testis ; Te tentacles ; Vd vas deferens ; Ye ventricle ; Wp ciliated furrow ; 

 Z posterior branch of anterior aorta. 



Section 2. Heteropoda.* 



The Heteropoda are free-swimming, pelagic Pectinibranchiates, with laterally- 

 compressed foot, taenioglossate radula, and otocysts near the cerebral ganglia. 

 They are without jaws. 



* C. Gegeubaur, " Untersuch. iib. Pteropoden u. Heteropoden," Leipzig, 1854. 

 T. H. Huxley, "On the Morphology of the Cephalous Mollusca," etc., Phil 

 Trails. 1853. 



