MALACOZOA. GASTEROPODA. PECTINIBRANCHIATA. 155 



Found by me, in August, 1 842, among shell sand, between 

 the mouths* of the Dee and the Don. 



4. Odostomia interstincta. Oval Ribbed Odostomia. 



Shell ovate-conical, of five. thin, transparent, glossy turns, 

 which are distinctly separated, rather flat, finely plicato-costate 

 transversely ; the mouth ovate, nearly half the whole length, 

 with the peristome rather thick, the pillar-lip not reflexed, but 

 ending in a very small tooth-like plait, and leaving exposed a 

 very narrow umbilical groove, the colour hyaline- white. Length 

 three-fourths of a twelfth, breadth about half the height. 



Easily distinguished from Odostomia spiralis by its more 

 ovate form, and its want of spiral striag. 



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

 mouths of the Dee and the Don. 



Montagu's figure of this species is too elongated, and that 

 of Odostomia spiralis too short. 



Turbo interstinctus. Mont. Test. Brit, 324. PL 12. f. 10. Odo- 

 stomia mterstincta. Flem. Brit. Anim. 310. 



5. Odostomia spiralis. Spiral Odostomia. 



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

 which are distinctly separated, nearly flat, finely ribbed trans- 

 versely, the last turn spirally striated in its anterior half, the 

 uppermost pair of striae deeper and running along the spiral 

 suture, which thus appears ridged ; the mouth widely ovate, 

 a third of the whole length, with the peristome of uniform 

 thickness, the pillar-lip not reflected, but ending in a small 

 tooth-like plait, and leaving exposed the narrow umbilicus, 

 from which a groove proceeds ; the colour hyaline-white. 

 Length one-twelfth of an inch, breadth nearly half the height. 



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

 mouths of the Dee and the Don ; and, in September, alive 

 from deep water off Aberdeen. 



Turbo spiralis. Mont. Test. Brit. 323. PL 12. f. 9. Odostomia 

 spiralis. Flem. Brit. Anim. 310. Turbo longitudinaliter striatus 

 quin que anfractibus, apertura subrotunda. Walker, Test. Min. 

 Rar. PL 2. f. 46. 



6. Odostomia semicostdta. Half-ribbed Odostomia. 



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

 which are distinctly separated, rounded, with obsolete longitu- 

 dinal striula?, and distant, delicate, transverse ribs, on the 



