154 MALACOZOA. GASTEROPODA. PECTIMBRANCHIAT.&. 



1. Odostomia unidentdta. One-toothed Odostomict. 



Shell ovate, of four or five moderately convex, rather thick, 

 glossy turns, distinctly separated by the suture ; the last turn 

 ventricose, longer than the spire ; the mouth ovate, acute be- 

 hind, with the outer lip thin, the inner reflexed, and termi- 

 nating in a thick tooth-like plait on the columella; the um- 

 bilicus small ; the colour white. Length two-thirds of a 

 twelfth, breadth half the length. 



Found by me and Miss Anne Macgillivray, in August, 

 1 842, among shell sand, on the beach, between the mouths of 

 the Dee and the Don; Cruden Bay, Mr. Murray. 



Turbo unidentatus. Mont. Test. Brit. 324. — Jammiaunidentata. 

 Brown, PI. 50. f. 34, 35. 



2. Odostomia plicata. Oblong Odostomia. 



Shell ovato-oblong, subturrite, of five or six thin, glossy, 

 transversely plicato-striate turns, which are distinctly separated, 

 rather flat, but convex toward the suture ; the mouth ovate, 

 rather narrow, less than half the whole length, with the outer 

 lip slightly thickened, the inner reflexed and ending in a 

 distinct plait, expanded over the narrow umbilicus, from which 

 proceeds a groove ; the colour hyaline-white. Length rather 

 more than a twelfth of an inch, breadth less than half the 

 length. 



Resembles Odostomia interstincta, but differs in being longer, 

 in having the pillar-lip reflexed, and the tooth-like plait large. 



Found by me, in August, 1842, in shell sand, between the 

 mouths of the Dee and the Don ; Cruden Bay, Mr. Murray. 



Odostomia plicata. Flem. Brit. Anim. 310. — Turbo plicatus. 

 Mont. Test. Brit. 37. PI. 21. f. 2. 



3. Odostomia scalar is. Scalar Odostomia. 



Shell ovato-conical, of five thin, transparent, glossy, faintly 

 striated, moderately convex turns, which are distinctly sepa- 

 rated by the spirato-canaliculate suture, toward which the 

 upper margin is suddenly inflexed ; the mouth ovate, nearly 

 half the whole length, with the peristome thin, the columellar 

 lip rather inflexed, and terminating in a prominent plait on the 

 columella ; no umbilicus ; the colour hyaline-white. Length 

 two-thirds of a twelfth, breadth half the height. 



This species differs from all the others in having the pillar- 

 lip ^flexed, in wanting the umbilicus, and in the subscalar 

 form of its spire. 



