366 MOLLUSC A. 



culum; the animal is like a true Nerita, and most generally the 

 columella is not dentated. It inhabits fresh water. 



A small species, very prettily coloured, abounds in the rivers 



of France; it is the Nerita Jluviatilis^ L. ; Chemn., IX, cxxiv, 



188(1). 



The columella in others, however, is finely crenulated(2), and of 



this number there are some in which the spire is armed with long 



spines — Clithon, Mont. (3) 



FAMILY II. 



CAPUL0IDA(4). 



Recent researches have convinced us that it is to the Tro- 

 choida that we must approximate this family, which contains 

 five genera, four of which are taken from the Patellae. They 

 all have a widely opened, scarcely turbinated shell, with nei- 

 ther operculum, cmargination nor siphon ; the animal resem- 

 bles the other Pectinibranchiata and has the sexes separate. 

 There is but one branchial comb transversely arranged on the 

 roof of the cavity, and its filaments are frequently very long. 



Capulus, Montf. — Pileopsis, Lam. 



A conical shell with a recurved and spiral summit, which has long 

 caused it to be placed among the Patellae; the branchiae are in one 

 rane:e under the anterior margin of the branchial cavity; the pro- 

 boscis is long, and there is a closely plaited membranous veil under 

 the neck; the eyes are at the external base of the conical tenta- 

 cula(5). The 



HiPPONYx, Defr. 



Would appear from the shell to be a fossil Capulus, very remark- 



(1) Add, Nerita turrifa, Chemn., rX, cxxiv, 1085. 



(2) Nerita puUigera, Chemn., loc. cit., 1878 — 1879; — N. virginea. List., 604, 

 606. 



(3) Nerita corona, Chemn., 1083, 1084. 



(4) M. deBlainville places most of them among his hermaphroditical, non-sym- 

 metrical ParacepJialophora; bat they all appear to me to be disecious. 



(5) Patella hungarica. List., 544 — 32; — Pat. calyptra, Chemn., X, clxix, 1643 

 ■ — 44; — Pat. mitriila, Gm., List., dxliv, 31. 



