VERTIGO. 173 



Inhab. marshy situations, on Isolepis fluctuans. 

 (Gray, 1817.) 



Animal grey-black and shining ; upper tentacles 

 short, inflated at the base, lower dot-like ; front of 

 head proboscis-like. 



Shell smaller than the last, of a deep chestnut- 

 brown colour, with the margin of the aperture 

 whitish ; teeth three above and three below, and one 

 on each side, and often a ninth tubercular tooth. 



It may easily be distinguished by the three very 

 discernible white teeth of unequal size within the 

 upper and truncated part of the aperture, whereas 

 there is only a single central one apparently visible 

 in the same position in V. pygmcea, and two in V. 

 substriata. The mouth varies with from six to nine 

 teeth. 



b. Shell cylindrical fusiform, sinistral ; mouth mar- 

 gined externally. (Vertigo Midler. Vertilla 

 Moq. Tand.) 



so. 7. VERTIGO pusilla. Wry-necked Whorl Shell. 

 Shell ventricose, attenuated, bald, rather 

 shining, very brittle, pale brown; whorls five ; 

 mouth subquadrate, rounded beneath ; plaits 

 six or seven, white, two or three on the column, 

 and four on the lips ; peristome thin ; umbilicus 

 rather narrow, (t. 7. f. 86.) 



Vertigo pusilla. Mutter, Verm. ii. 124. ; Alder, Mag. Zool. 

 and Sot. ii. 112. ; Jeffreys, Linn. Trans, xvi. 361. Jaminia 

 heterostropha. Risao, iv. p. 91. Vertigo heterostropha. 

 Turton, Man. 105. f. 88.; Leach, Moll. Syn. 94. Pupa 

 Vertigo. Drap. Tabl 57., Hist. Moll p. 61. t. 3. f. 34, 35. 

 Pupa pusilla. L. Pfeiffer, Mon. H. ii. 364. ; Forbes and 

 Hanley, B. M. iv. 111. t. 130. f. 8. Helix Vertigo. Gmel. 

 S. N. 3664. Turbo Vertigo, var. Mont. T. B. 365. 



