100 MALACOZOA. GASTEROPODA. PULMOBRANCHIATA. 



vex turns, which are transversely striated and distinctly sepa- 

 rated by the suture ; the aperture nearly circular, the peri- 

 stome thin, but with a strong, convex external rib behind it 

 on the outer lip ; a single obtuse, often obsolete, tooth in the 

 middle of the columellar space between the two lips, and uncon- 

 nected with either ; the umbilicus narrow ; the colour olivace- 

 ous, or yellowish-grey, the peristome and rib greyish or 

 yellowish-white. Length two-twelfths, breadth about half 

 the length. 



The animal has the foot oblong, rounded behind, trans- 

 parent, hyaline-white; the neck and head brownish-black; 

 the tentacula dusky, the upper long, subulate, clavate, the 

 lower short. 



Very nearly allied to Pupa umbilicata; but easily distin- 

 guishable, it being more cylindrical, with the last turn smaller, 

 the tooth or plait not connected with the outer lip, as in that 

 species, but free, and placed nearly half-way between the two 

 lips, considerably within the mouth. Sometimes the tooth is 

 entirely absent, the shell remaining in other respects the 

 same. The mouth, instead of having the margin flattened 

 and expanded, is thin-edged, but with a strong convex external 

 rim. Individuals much exposed to the weather, are often grey, 

 or whitish, and opaque ; those well sheltered, and especially 

 such as live in grassy places, are olivaceous, or light brown, 

 and more or less glossy and transparent. 



Found by me, on the 5th of August, 1842, on the banks of 

 the Bay of Peterhead ; and on the 6th among the sand-banks 

 of the Bay of Cruden, and on rocks, under stones, and among 

 moss, at Slains Castle, and at the Bullers of Buchan ; in all 

 which places it is very abundant. In the end of August I 

 found it on the inner sand-hillocks of the Links of Old Aber- 

 deen, where it is abundant in some places, while Pupa umbili- 

 cata is equally so in others. 



Pupa marginata. Drap. Moll. Terr, et Fluv. 61. PI 3. f. 36, 37, 

 38. Pupa marginata. Flem. Brit. Anim. 268. Pupa muscorum. 

 Lamk. Syst. Ed.2. viii. 180. Pupa marginata. Gray's Turton, 196. 



GENUS 8. VERTIGO. WHORL-SNAIL. 



Animal with the body elongated, spiral ; the head 

 with the two upper tentacula elongated subulate and 

 clavate, the lower very short or rudimentary ; the foot 

 small, elongated ; the orifice of the pulmonary cavity on 

 the right side of the neck, near that of the intestine j 



