APPENDIX. 281 



obtusely with a light, horny, thin, obliquely striated operculum, 

 seated on a simple lobe that is scarce distinct from the upper part 

 of the foot, at its junction with the body." 



Vol. iii. p. 301. Odostomia dolioliformis. 



The animal, according to Mr. Clark, is hyaline pale azure. It 

 has longer and not so triangular tentacula than its congeners, 

 nor are they furnished with such broad lateral membranes, nor 

 do they coalesce so decidedly. They are tipped with flake 

 white. The eyes are at their internal bases. The foot is short 

 and broad, truncate anteriorly, and exhibits a curious trilobed 

 appearance. This mollusk inhabits the littoral zone. 



Vol. iii. p. 303. Odostomia decussata. 



The animal, according to Mr. Clark, is hyaline white, except 

 the mentum, which is pink and less lobed, though more truncate 

 than in congeneric species. The tentacula are triangular and 

 pointed, with coalescing lateral membranes. The eyes are ele- 

 vated on minute prominences, and are very close together at the 

 inner bases of the tentacula. This mollusk is not shy ; it in- 

 habits the circum-littoral belt, in twelve fathoms water, at 

 Budleigh Salterton, 



Vol. iii. p. 308. Odostomia GuLSON.ffi, Clark. 



Plate CXXXII. fig. 6. 



Chemnitzia Gulsonce, Clark, Ann. Nat. Hist, new ser. vol. vi. p. 459, and 

 vol. viii. p. 108. — Jeffreys, do. vol. vii. p. 27. 



Shell thin, semitransparent, smooth, white, glossy, of a slender 

 turreted form, subcylindrical in the middle, moderately tapering 

 and blunt-topped above ; with a peculiar lateral projection of the 

 last whorl on the side of the mouth. Whorls from five to six, 

 distinctly divided by a more or less slanting suture ; rounded, or 

 at least decidedly convex, of rather quick longitudinal increase, 

 and somewhat high, the breadth in the penult volution being 



VOL. IV. o o 



