EUCHELUS. 431 



cled by numerous unequal beaded spirals, of which two are more prom- 

 inent on the upper, 3 or 4 on the body-whorl. Typically, these more 

 prominent ones are elevated into spiral lamellae, but they are often 

 not greatly larger than the others. There are generally about 12 

 spirals on the penultimate whorl. Body-whorl globose, convex ; 

 aperture rounded, outer and basal lips thick, finely crenulate. finely 

 plicate inside; columella concave, its edge smooth, and bearing a 

 small denticle near the base, excavated at the position of the closed 

 umbilicus, and rugose. Alt. 28, diam. 23 mill. 



Indian Ocean. 



TrocJius quadricarinatus CHEMNITZ, Conchyl. Cab. xi, p. 167, t. 

 196, f. 1892, 1893 (1795). Monodonta tricarinata LAM., An. s. 

 Vert, vii, p. 36. DELESSERT, Rec. deCoq., t. 36, f. 8. Troehus tri- 

 caruiatas Lam., PHIL., Conchyl. Cab., p. 171, t. 27, f. 8. FISCHER, 

 Coq. Viv., p. 287, t. 93, f. 1. Troehus oxytropis PHIL., Zeitschr. f. 

 Mai. 1848, t. 39, f. 1. 



The typical form is that represented in fig. 9. Figures 10 and 11 

 represent less strongly characterized shells. The latter approach E. 

 asper, and may be found to be connected by intermediate forms. 



Tr. ojcytrnin* Phil. (pi. 37, figs. 14, 15), seems to be merely a young 

 specimen of the typical form. Fully adult quadricar mains seems to 

 be always imperforate, but specimens with a small umbilicus may 

 occur. (Vide Fischer, loc. cit.~). Young shells have a large, deep 

 umbilicus. 



E. ASPER Gmelin. PL 38, figs. 13, 14. 



Shell imperforate in adult specimens, conoidal, thick, dull ashen, 

 dotted with brown, rosy, and black ; whorls 65-6, convex, separated 

 by profound sutures, the first eroded, the rest rough, ornamented 

 with close, granulose, unequal cinguli, two on the upper, 3 or 4 on 

 the last whorl more prominent ; penultimate whorl with 12-15 lira? ; 

 last whorl globose rounded, descending, convex beneath ; aperture, 

 ovate-rounded, the margins nearly continuous, plicated finely all 

 around, columella arcuate, base dentate. Alt. 26, diam. 24 mill. 



Indian Ocean. 



Troehus asper GMEL., Syst. Xat. xiii, p. 3583. PHIL., Conchyl. 

 Cab., p. 172, t. 27, f. 11. FISCHER, Coq. Viv., p. 291, t. 94, f. 1. 

 E. proximus A. AD., P. Z. S. 1854, p. 316. 



Probably the last is a form of this species. Typically, asper is 

 more elevated with smaller, more numerous spirals. I have given 



