CHEMNITZIA. 415 



laria basi coalita, lateribus membranaceis, apicibus lobis minutis, 

 aut simulantibus, instructis. Oculi, ad basin centralem vel in- 

 ternam tentaculorum immersi. Pes characterem nullum constan- 

 tem exhibens. 



Testa spiralis, Isevis, vel costata, vel lineis spirata, aut decussata, 

 anfractibus tribus ad octodecim instructa ; apertura ecanaliculata ; 

 latus columnare denticulo saepe munitum, ssepe muticum. Apex, 

 in gyrum sequentem reflexus. Operculum corneum, vel subtes- 

 taceum, subovale, striis ellipticis notatum, subspiratum, area 

 inferiori sub nucleo, apophysi semper instructa. 



C. PALLIDA, Mont, certe. 



Odostomia eulimoides, Brit. Moll. hi. p. 272, pi. 95. f. 1, 2, 3. 



O. ? pallida, Brit. Moll. iii. p. 307, pi. 98. fig. 4, and iv. p. 274. 



O. notata, 0. albella, O. dubia, O. alba, O. nitida, O. rissoides, 



O. eulimoides, O. glabrata, auct. variorum*. 

 O. dubia, Brit. Moll. iii. p. 276, pi. 94. f. S, and iv. p. 2/9. 

 0. alba, Brit. Moll. iii. p. 278, pi. 96. f. 9. 

 O. nitida, Brit. Moll. iii. p. 280, pi. 94. f. 6. 

 O. glabrata, Brit. Moll. iii. p. 283, pi. 98. f. 3. 

 O. rissoides, Brit. Moll. iii. p. 284, pi. 96. f. 4 (5, var. albella), and iv. 



p. 279. 



Animal of six spiral turns ; mantle plain. Foot short, trun- 

 cate in front,, slightly auricled, but not emarginate or hollowed 

 out in the centre, as in its congener below, Chemnitzia acuta 

 rounded posteriorly, and terminating suddenly in a short 

 point; it is powdered on its upper surface with pale gold- 

 coloured minute points, and in some specimens with sulphur- 

 yellow dots ; beneath the same colours prevail, though less 

 intensely : it has a light corneous, simple, not spiral, suboval 

 operculum. The organ above the foot, and under the tenta- 

 cula, termed by us the rostrum, and by others the mentum, is 

 marked on each side with a pale yellow longitudinal line ; on 

 the quiet march it is short, thick, flat, slightly bevelled at the 

 sides, truncate and dilated at the extremity ; but when the 

 animal is disturbed, it presents many phases of figure, which, 

 without great care, may occasion discrepancies in the de- 



* Figures of most of these varieties may be seen in that valuable vade 

 mecum, the ' British Mollusca.' 



