NERITA. 1005 



vex, wrinkled and tuberculated, and has two or three strong 

 teeth on its margin. 



UNDULATA. 60. Shell with about thirty transverse 

 ribs, and the summit obtuse ; outer lip slight- 

 ly striated and toothless ; inner lip wrinkled 

 and denticulated. 



Nerita undulata. Gmelin, p. 3678. 



Nerita, No. 106. Schroeter Einl. ii. p. 336. 



Nerita undata subtilior et levior. Chemnitz, v. p. 301. 1. 191. 

 f. 1970 and 1971. 

 Inhabits the East Indian Seas. Chemnitz. 

 This shell appears to be nearly of the same size and shape as 



the foregoing, but is said to be thinner, with the ribs much 



narrower, and the summit not pointed ; it is of a greyish 



colour, longitudinally waved with black. 



EXUVIA. 61. Shell transversely ribbed, with the 



summit very obtuse ; lips toothed, and the 



inner one slightly concave and tuberculated. 



Nerita Exuvia. Linnaus S^st. Nat. p. 1255. Bo7'n Mus. 



p. 409. Chemnitz, v. p. 302. t. 191. f. 1972 and 1973. 



Schroeter Einl. ii. p. 303. Gmelin, p. 3683. Schrei- 



bers Conch, i. p. 329. 



Lister Conch, t. 596. f. 5, and t. 599. f. 15. Gualter, t. 



66. f. CC. ? Seha, iii. t. 59- f. 4 to 10. Geve, t. 23. f. 



240. Knorr, iu. t. 1. f. 5. 



Inhabits the coasts of America and Asia. Linnmis, Jamaica. 



Liister. 

 Shell about half or sometimes three-quarters of an inch long, 

 and the breadth rather exceeds the length ; it has from fif- 

 teen to nineteen broad flattened ribs ; the inner lip is slightly 

 concave, and studded with small tubercles, and has two or 

 three minute teeth on the margin ; the colour is black, with 

 white spots or longitudinal undulated stripes. Some of the 

 figures which are quoted in the Systema Naturze belong to 

 2V. plexa, and Linneeus probably considered it to be only a 

 Variety of this species. 



QUADRICOLOR. 62. Shell transversely ribbed, with 

 the upper ribs larger, and the summit acute ; 

 lips toothed, and the inner one wrinkled. 



Nerita quadricolor. Gmelin, p. 3684. Schreibers Conch. 

 i. p. 330. 



