MALACOZOA. GASTEROPODA. PECTINIBRANCniATA. 59 



longer than tlie spire, the aperture ovate, with a thick 

 tooth-Hke plait. Umis, one ; dens, tooth. 



2. Odostdmia pUccita. — Shell ovato-oblong, of five or 

 six glossy, transversely plicato-striate turns, which are 

 rather flat, but convex toward the suture, the aperture 

 ovate, with a distinct plait. PUcatus, having a plait. 



3. Odostdmia scaldris. — Shell ovato-conical, of five 

 thin, transparent, glossy, faintly striated, moderately 

 convex turns, the suture canaliculate, the aperture ovate, 

 with a prominent plait. Scalaris, like a stair. 



4. Odostomia interstincta. — Shell ovato-conical, of 

 five thin, transparent, glossy, rather flat, finely phcato- 

 costate turns, the aperture ovate, nearly half the whole 

 length, with a very small plait. Interstinctus. 



5. Odostomia spiralis. — Shell ovato-conical, of five 

 thin, transparent, glossy, nearly flat, finely ribbed turns, 

 the last spirally striated in its anterior half, the two 

 upper striae deeper and running along the spiral suture. 

 Spiralis, sj^iral, in reference to the lines mentioned. 



6. Odostomia semicostdta. — Shell ovato-conical, of five 

 thin, transparent, glossy, rounded turns, marked with 

 obsolete longitudinal striulse, and distant, delicate, trans- 

 verse ribs on the upper half of the last turn, no plait on 

 the columella. Semtcostatus, half-ribbed. 



7. Odostomia p>licdtula. — Shell ovato-conical, of five 

 rather thick, opaque, glossy, flat, finely plicato-striate 

 turns, the last with the plicae ending about the middle, 

 and succeeded by three or four spiral striae, the terminal 

 jjart plain ; a very sUght plait, no umbilicus. Plicatulusy 

 finely plaited. 



8. Odostdmia MarioncB. — Shell ovato-conical, of five 

 convex, thin, transparent rather glossy turns, finely pli- 

 cate transversely, delicately striated spirally, and having 

 the upper margin in the form of a rib. Named after 

 Miss Marion Macgillivray. 



9. Odostdmia Annce. — Shell oblongo-turrite, of five 

 rather thick, opaque, glossy turns, the last convex and 

 proportionally larger, the rest flattened, the aperture ovate. 



