GASTEROPODA PECTINIBRANCHIATA. 59 



A small species, the Trochus tesselatus, L. ; Adans., Senes^., 

 XII. 1 ; List., 642, 33, 34, with a brown shell spotted with 

 whitish, is very abundant on the coast of France*. 



Phasianella, Lcmi. 



An oblong or pointed shell, similar to that of several Bulimi and 

 Lymnsese ; the aperture also higher than it is wide, and furnished 



with a strong operculum; base of the columella sensibly flattened, 

 but no umbilicus. 



They inhabit the Indian Ocean, and are much sought for by col- 

 lectors on account of the beauty of their colours. The animal is 

 provided -with two long tentacula, witli eyes placed on two tubercles 

 at their external base, and with double lips that are emarginated and 

 fringed, as well as the wings, each of which has three filaments f. 



Ampullaria, Lam. 



A roimd, ventricose shell, with a sliort spire, as in most of the He- 

 lices; the aperture higher than it is wide, and provided with an oper- 

 culum ; the columella umbilicatcd. 



They inhabit the fresh or brackish Avaters of hot countries. The 

 animal has long tentacvda, and eyes placed on pedicles at their base. 

 In the roof of the respiratory cavity, by the side of a branchial comb, 

 according to the observations of Messrs. Quoy and Gaymard, is a 

 large pouch, without an issvie, that is filled with air, and Avhich may 

 be considered as a natatory bladder :|:. 



The Laxist.e, Montf., are Ampullaria^, with a large, spiral, con- 

 voluted umbilicus §. 



Helicina, Lam.\\ 



Judging by the shell, the Helicinae are Ampullariee in which the 

 margin of the aperture is reflected^. 



When this reflected margin is trenchant, they are the AmpuUincs, 

 Blainv. ; and when it is in an obtuse ridge, the Oli/girce, Say. 



* Add, Trochus labeo, Adans., Seneg., XII, List., 68, 442 ; Troch. Pharaonius, 

 List., 637, 25 ; — Tr. rustkus, Chemn., V, clxx, 1645, 46; — Tr. niyerrimits, lb. 47 ; 

 — Tr. (egijpiim, Id., clxxi, 1663, 4; — Tr. viridulns, lb. 1677; — Tr. carneus, lb. 

 1682 ; — Tr. aUndus, Born., XI, 19, 20 ; — Tr. as^per, Chemn., lb., clxvi, 1582 ; — Tr. 

 citrinus, Knorr., Del., I, x, 7; — Tr. granatum, Chemn., V, clxx, 1654 — 55; Tr. 

 crocatus, Born., XII, 11, 12; — Turbo atratus, Chemn., V, clxxvi, 1754 — 55; — 

 Turbo dentaius, Id., clxxviii, 1767, 8, &c. 



t Buccinum tritonis, Cliemn., IX, cxx, 1035, 1036; — Helix solid a, Born., XIII, 

 18, 19. 



+ Helix (tmpuUacea, L., List., 130 ; — Bulimus iirccus, Brug., List., 125, 26. 



§ Ampulla carinafci, Oliv., Voy. en Turq., pi. xxxi, f. 7, copied Blainv., Malac, 

 xxxiv, 3. 



II Montfort has changed the name Helicina into Pifonnilla, but it has not been 

 adopted, and can only be quoted as a synonyme. 



^ The Hel striala, Blainv., Malac, xxxv, iv. 



