242 On some new and peculiar Mollusca. 



of these striae is more prominent than the three below it, so as 

 to give an angnlated appearance to the whorls ; the two sets 

 of strige cross one another, the result being a faint cancellation j 

 top whorls smooth : colour whitish : spire slender ; apex 

 blunt: whorls 12-15, convex, gradually enlarging: suture 

 deep : mouth roundish-oval : outer lip thin : inner lip folded 

 back a little at the base. L. 0'7. B. 0-125. 



Station 12, 1450 fms. ; two imperfect specimens. 'Porcu- 

 pine ' Expedition, 1870, off the coast of Portugal, 994 fms. ; 

 a single specimen. 



One of the * Valorous ' specimens, which is fragmentary, 

 measures 0'15 inch in breadth, and shows that the shell attains 

 greater dimensions than those given in the above description. 

 It is a verj elegant species. 



Pyramidellidae. 



Odostomia albula, Fabricius. 

 Turbo alhuhis, Fabr. Fn, Gr. p. 394. 



Body milk-white, with a faint tinge of yellowish-brown : 

 head snout-like, cloven in front, with smooth or plain edges ; 

 tentacles compressed, leaf-like or triangular, and folded inwards; 

 the edges are microscopically notched or saw-like, but not 

 ciliated : eyes small, sessile on the inner bases of the tentacles : 

 foot rather short and thick, closely ciliated in front, with the 

 cilia in active and incessant motion, squarish and having 

 slightly angular corners, bluntly pointed behind : opercidum 

 ear-shaped, thin, paucispiral, marked with flexuous strife, and 

 similar to that of other species of Odostomia. The animal is 

 very shy or sluggish. 



Holsteinborg, 10 fms. Greenland (Fabricius, Moller). 

 Spitzbergen Is-sound, 50 fms. (Torell) ! North Japan (St. 

 John) ; variety, anfractibus minus convexis ! Some of the 

 Japanese specimens have on the pillar a slight indication of 

 the usual fold or tooth. Mr. A. Adams described this variety 

 as Menestho sidcatina. 



The specific name is too much like alhella ; but it may be 

 more inconvenient to change it. Otherwise I would have 

 proposed Fahricii. 



I cannot distinguish this species from Odostomia by any 

 generic character. The animal is similar ; and the shell has 

 the same heterostrophe and inverted apex. Moller says also 

 that it wants the lingual membrane or odontophore. He also 

 noticed the operculum, which Fabricius coukl not detect — 

 " operculum nullum." It is the type of Moller's genus 

 Menestho. Menke says, in his ' Zeitschrift fur Malakozoolo- 



