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 

 pillar; inner lip generally spreading, 

 • flattened, and concave ; body-whorl 

 convex beneath, rounded on the sides ; 

 aperture obliquely round ; spire short, 

 depressed, pointed. (^^.111.) in 



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

 magus. Jb. 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. 109- 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. Lam. No. 47. granatina. Mart. 170. f. 

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



erythroleuca.Ib.l62.f.l529. Australis. Zool. Jour. v. 331. 



MoNODONTA Lam. Base of the pillar forming a distinct 

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

 aperture striated ; outer lip not thin at the margin. 



Eknchus Humph. Shell smooth ; spire considerably 



* Except in Elcnchus and Echinidea. 



