276 PYRAMIDELLIDJi. 



terior part of the foot not being hollowed ont. There are 

 five or six varieties, -which merely differ in the contour of 

 the shells and slightly in the coloration. The principal 

 habitat of this species is at the back of the auricles of the 

 Pecten opercularis, from the coralline zone, where they may 

 be seen in clusters, imbedded in animal mucus. This is the 

 most common species." — Clark, MSS. 



A list of localities would be superfluous. There are few 

 explored portions of our coast, where the dredge fails to 

 procure it ; it more especially, however, abounds on the 

 coasts of South Devon and Dorset. 



O. DuiiiA, Jeffreys. 



Obloug-conoid, smooth, iYory--\vhite, subperforated ; \vhorIs 

 convex, but not ventricose, of quick increase ; body nearly equal 

 to the spire, not at all angulated at its periphery, a little pro- 

 duced at the base. Mouth narrow, gradually and acutely con- 

 tracted above, not large ; pillar lip a little curved, not broadly 

 reflected ; fold distinct but retired ; throat smooth. 



Plate XCIV. fig. 8. 

 Odosiomia duhia, Jeffreys, Ann. Nat. Ilist. new ser. vol. ii. p. 338. 



The form of this negatively characterised Odosiomia, 

 which is thin, glossy, semitransparent, smooth, and white, 

 is suboval, but tapers above to a small but blunt apex. It 

 is composed of from five to five-and-a-half volutions, that 

 are convex or even somewhat rounded, of quick longitudinal 

 increase, much attenuated posteriorly, but neither flattened 

 nor scalar beneath the moderately oblique and very distinct 

 (yet not canaliculated) suture that divides them from each 

 other. The penult, and often the antepenult turn likewise, 

 is decidedly high. The body, which vies with the spire in 

 It-neth, is neither at all angnlated at the periphery, nor 



