GASTEROPODA PECTINIBKANCHIATA. 63 



ranged on the roof of the cavity, and its filaments are frequently very 

 long. 



Capulls, Monlf. — 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 

 range under the interior 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 tentacula*. 

 The 



HippONYX, Defr. 



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

 able, however, for a bed formed of calcareous matter, on which it 

 rests, and which probably exuded from the foot of the animalf. 



Crepidula, Lam. 



The shell oval, with an obtuse horizontal point, directed obliquely 

 backwards and laterally; the aperture forming the base of the shell, 

 which is half closed beneath and behind by a horizontal plate. The 

 abdomJnal sac which contains the viscera is on this plate, the foot 

 beneath, and the head and branchiae forwards. Tlie latter consist of 

 a range of long filaments attached under the anterior margin of the 

 branchial cavity. Tlie eyes are at the external base of two conical 

 tentacula \. The genus 



PiLEOLus, Soioerbij, 



Appears to consist of Crepidulae, in which the transverse plate occu- 

 pies half the aperture ; their shell, however, is more like that of a 

 Patella §. They are only found fossil. 



Septaria, Fer.— Navicella, Lam. — Cimber, Mont/., 82. 



The shell resembles a Crepidula, except that the summit is symme- 

 trical and laid on the posterior margin, and that the horizontal plate is 

 less salient. The animal is also provided Avith an additional, irre- 

 gularly shaped, testaceous plate, horizontally connected Avith the 

 superior surface of the muscular disk of its foot, and covered by the 

 abdominal sac, which it partially suj^ports. It is probably analogous 

 to an operculum, but does not exercise its functions, being, in a 

 measure, situated internally. The animal has long tentacula, at 



* Patella hungarica, List., 544—32 \—Pat. cahjpfra, Chemn., X, clxix, 1643— 

 44 ; — Pat. mitruht, Gm., List., cxliv, 31. 



t Patella comucopice, Lam., Knorr., Petrif., II, part ii, pi. 131, f. 3, andBlainv,, 

 Malac. 



+ Patella fornicaf a, List. 545, 33, 35 ; — P. aculeata, Chema., X, clxviii, 1624— 

 25 ; — P. Goreemis, Martini, I, xiii, 131, 132 ; — P. solea, Naturf., XVIII, ii, 15 ; 

 — P. crepidida, Aians. Seneg., I, ii, 9; — P.porcellana, List., 545, 34. 



§ Pileolus plkatiis, Sowerb. ;— Pii. Icevis, Id., Genera of Shells, No. IX ;— Pi?. 

 neritoides, Desh., Ann. des Sc, Nat., I, xiii, 3, a, b, c. 



