990 NERITA. 



Linnaeus says that this shell is like N. littoralis, but is of a 

 horn -colour, and the summit not carious; Gualter's figure, 

 which Linnaeus has quoted, is much more like N.Jluviatilis, 

 and Chemnitz has quoted the Linnaean N. lacustris for a 

 Variety of that species. 



DUBIA. 27, Shell ovate, thin, pellucid, shining, of a 

 dull yellow colour, variegated with black ; 

 outer lip acute, and the inner lip glabrous. 



Nerita dubia. Chemnitz, v. p. 324. t. 193. f. 2019 and 



2020. Gmelin, p. 3076. Schreihers Conch, i. p. 332. 

 Nerita, No. 120. Schroeter Einl. ii. p. 340. 

 Geve, t. 24. f. 248. 



Inhabits 



This shell appears by Chemnitz's figures to be about an inch 

 long, and three-quarters of an inch broad, and is said to be 

 very rare ; the body-whirl is large, and the spire very small, 

 with the summit slightly produced ; the colour is brownish 

 yellow, with black spots and longitudinal streaks in trans- 

 verse rows. Schreibers has placed this shell in the third 

 division. 



MARGINATA. 28. Shell sub-globular, thin, tubercu- 

 lated, with decussated striae, and black with 

 ochraceous spots ; aperture marginated. 



Nerita marginata. Gmelin, p. 3677. 



Nerita, No. 226. Schroeter Einl. ii. p. 371. t.4. f. 16. 



Inhabits 



This shell appears by Schroeter's figure to be about ten lines 

 long, and is distinguished by having the aperture marginated 

 outwardly ; the inside is said to be glabrous, and the pillar- 

 lip fiat, wrinkled and luberculated. 



*** Imperforate, with the pillar-lip toothed. 



PULLIGERA. 29. Shell smooth, unpolished, with 

 the spire excavated at the summit, and the 

 margin of the inner lip crenulated. 



Nerita pulligera. Linnccus St/st. Nat. p. 1 253. Born Mus. 



p. 402. 1. 17. f. 9 and 10. Schroeter Fluss. p. 215, and 



Einl. ii. p. 289. Chemnitz, ix. part 2. p. 64. t. 124. 



f. 1078 and 1079. Gmelin, p. 3678. Schreiben Conch. 



i. p. 326. 

 Nerita rubella. Muller Ferm. ii. p. 195. 



