254 MARSHALL : ADDITIONS TO ' BRITISH CONCHOLOGY.' 



Found in Torbay ; Killala Bay, west coast of Ireland ; and 



in the Minch. 



There has been some confusion and mixing-up of O. war- 

 rent and O. obliqua. This should not have occurred, as Clark 

 wrote long ago that 'both animal and shell are very distinct 

 from O. obliqua.'' The latter is really a rare species, very true 

 to form, and sculptured throughout with spiral stri?e, which may 

 be seen with a lens. It is not 'shaped like a miniature Li)nnaa 

 stagnalis,' ^s, Jeffreys states, nor is the spire 'long and tapering'; 

 that applies to O. warreni, whereas O. obliqua is shaped like a 

 miniature Limticeapalus/ris, and forms a long oval, having a short 

 spire and a long body-whorl. The nucleus is twisted upwards 

 and exposed, while in all its congeners it is sunk. Jeffreys' 

 figure is not very good ; there should be no umbilicus, the spire 

 should be shorter, and the last whorl longer. Forbes and Han- 

 ley's figure is taken apparently from an O. diaphana, which 

 Sowerby seems to have followed, while the latter's figure of 

 O. diaphana would do for O. insculpta var. losvissima, but not 

 this. O. war/eni, on the other hand, is a comparatively com- 

 mon shell, widely diffused on our coasts. It is also extremely 

 variable in shape, the extreme forms being most marked, and 

 liable to be taken at first sight for different species. Jeffreys' 

 type figure, from the Shetlands, of which I have specimens, 

 is different from any I have from at least twenty other locali- 

 ties, and numbering hundreds of specimens. The shell always 

 has a larger body-whorl than this figure ; the whorls are 

 turreted so as to give the spire a telescopic appearance, espe- 

 cially when viewed with the mouth downwards; it is sculptured 

 with spiral stride at the base only of each whorl, and it has a 

 large and deep umbilicus visible at all stages of growth ; the 

 suture is deeper and less oblique, the apex abruptly truncated, 

 and the aperture shorter and wider. It will thus be seen that 

 the two species have very few characters in common. Forbes 

 and Hanley's figure of this is nothing like, neither is Sowerby's. 

 O. spiralis var. coarctata Marsh. (See 'J. of C.,' Apr, 1891). 



J.C, vii., Oct. 1893. 



