PART II. TROCHIN^. ] 351 



Trochus Linn. Umbilicus either very open or small^ 

 but always apparent ; base of the outer ^^^^^^ 

 lip sinuated where it unites with the ^^^^SfJ^ 

 pillar ; inner lip generally spreading^ ^K\t"^^S^!) 

 flattened, and concave ; body-whorl ^^^^^^ 

 convex beneath, rounded on the sides ; \(^£<x^ 

 aperture obliquely round ; spire short, \^^^^^ 



depressed, pointed, (^fig. 111.) lU ^■^-^_/ 



T. pica. Mart. 176. f. 1750. cinerarius Linn. Mart. 171. 

 magus. lb. 171. f. 1656. f. 1686. 



Pagodella Sw. Trochiform ; generally thin, and always 

 not perlaceous ; aperture and pillar perfectly united 

 and entire ; operculum horny. 



P. major. Mart. 163. f. 1541, 1542. 

 tectum-persica. lb. f. 1543, 1544. 



Trochidon Sw. Trochiform ; spire more elevated than 

 in the last; but the base of the pillar either angulated, 

 umbilicus none, or forming a tooth more or less deve- 

 loped, often with a lateral, depressed groove, but no 

 umbilicus ; margin of the outer lip thin, the inside 

 rarely striated, {fig. IO9. d.) 



T. labeo. En. Meth. 447. viridis. lb. 447. f 2. 

 f. 1. canalifera. lb. f. 5. 



Calliostoma Sw. Imperforate : spire elevated, acute ; 

 aperture broader than high, transversely ovate, hardly 

 sinuated at the base, and slightly oblique; shells 

 always smooth, and often polished : representing 

 Cidaris. 



zizyphina. Pen. Zool. pi. 80. annulata. Ch. 165. f. 1551-2. 



f. 103. doliata. lb. f. 1579 — 1583. 



conuloides. Lara. No. 47. granatina. Mart. 170. f. 

 conula. Mart. 166. f. 1588. 1654, 1655. 



erythroleuca.Ib.l62.f,1529. Australis. Zool. Jour. v. 331. 



MoNODONTA Lam. Base of the piUar forming a distinct 

 tooth ; umbilicus deep*, with a deep groove below ; 

 aperture striated ; outer lip not thin at the margin. 



Elenchus Humph. Shell smooth ; spire considerably 



* Except in Elenchus and Echinidea. 



