ODOSTOMIA. 353 



0. INTERSTINCTA, Mont. PL 77, figs. 16, IT ; PI. 78, fig. 21. 



Rather solid, semi transparent, glossy, with numerous strong, 

 slightly curved longitudinal ribs, broader than the interstices, 

 ending at two or three rows of obscure spiral striae just below 

 the periphery, forming punctures in the interstices, the upper 

 whorls similarly marked just above the suture, base generally 

 smooth, color white ; whorls 5-6, compressly convex, shelving 

 abruptly towards the suture, each with a thickend rim round the 

 top, suture narrow, but deeply excavated ; outer lip flexuous, 

 slightly sinuated above ; umbilicus none, or a narrow chink in 

 old specimens ; tooth short and retired, but strong. 



Length, 3 mill. 



Europe, Canary 7s., Madeira. 

 Yar. TEREBELLUM, Phil. Fig. 17. 



Much larger, with elongated spire, ribs more oblique, espe- 

 cial^ on the body-whorl, tooth prominent. 



0. Moulinsiana, Fischer (figured), appears to be equivalent 

 to this. 



Yar. SUTURALIS, Phil. Fig. 21. 



Smaller, narrower and more cylindrical than the type, costae 

 very fine and well curved. 



0. striata, Phil, (figured), is a synonym. 



Yar. GRACILIS, Phil. 



Shining, longitudinally obliquely ribbed, with a single spiral 

 line on the upper whorls, two on the body-whorl; whorls 5, 

 suture well impressed. A minute, rather doubtful shell, 

 variously interpreted ; the following species has been referred 

 to it. 0. ambigua, Weinkauff, is identical. 



0. EMACTATA, Brusina. PL 78, fig. 22. 



Shell narrow, cylindrical, having 5 convex whorls besides the 

 embryonic one, with strong longitudinal ribs and subequal inter- 

 spaces, periphery marked by a spiral thread, below which, on 

 the body-whorl, the ribs become evanescent ; tooth minute. 

 Length, 2-1 mill. 



Mediterranean. 



It is 0. pygmsea, Brus., not Grateloup ; 0. Silvestri, Arad. 

 23 



