354 OBOSTOMIA. 



0. MONOZONA, Brusina. PL 78, fig. 18. 



Whorls 4, convex, longitudinally ribbed, with wider intervals, 

 ribs disappearing gradually towards the base of the last whorl, 

 a few spiral striae on the interstices about the middle of the 

 last whorl; white; tooth small. Length, 2 mill. 



Mediterranean Sea. 

 0. INTERMIXTA, Monts. PI. 78, figs. 19, 20. 



Whorls 4, besides the embryonic, slightly rounded, with 

 strong longitudinal ribs, nearly straight, and fewer in number 

 than in 0. interstincta , a spiral thread near the suture, and on 

 the periphery of the last whorl, tooth minute. 



Mediterranean. 



It is 0. Jeffrey si, Bucq., Dautz. et Dollf., not Koch and 

 Weichman, the latter a miocene species of earlier description. 



Tar. FLEXTCOSTA, Bucq., Dautz. Dollf. Fig. 20. 



More elongated than the type, the ribs flexuous. 

 0. PENCHYNATI, Bucq., Dautz. Dollf. PI. 78, fig. 25. 



Closely related to 0. inter stincta and 0. intermixta, but dis- 

 tinguished by its short pupoidal form and turriculated whorls. 



Length, T6 mill. 



Mediterranean Sea. 

 0. ABBREVIATA, Monts. PI. 78, fig. 23. 



Solid, opaque, gloss3 r , with about a dozen strong sharp longi- 

 tudinal ribs, terminating abruptly at the bluntly angulated per- 

 iphery ; white ; whorls 4, besides the nucleus, suture shallow ; 

 tooth small, indistinct; umbilicus none. Length, 2'5 mill. 



Mediterranean Sea. 



Described by Jeffreys as 0. brevicula, preoccupied by Monte- 

 rosato. 



0. SPIRALIS, Mont. PI. 78, fig. 52. 



Rather solid, semitransparent, glossy, with about 30 straight 

 or slightly curved ribs, broader than the interstices, terminated 

 at the angulated periphery by a series of spiral basal striae, 

 which are often closely punctured; whorls 5-6, flatly convex, 

 shelving towards the suture which is narrow and deep; outer lip 

 sinuous above; umbilicus a rather prominent chink; tooth very 

 short, blunt and obscure. Length, 3 mill. 



Europe. 



