1917.] NATURAL SCIENCES OF PHILADELPHIA. 179" 



Odostomia santodomingensis n. n. 



Aclis polila Gabb, Trans. Amer. Philos. Soc, XV, 1873, p. 226. Not Odo- 

 stomia poliia of Bivona or of Pease. 



The form is somewhat cylinclric. The surface is marked with very 

 fine growth-Unes only. Whorls are weakly convex except the first 

 which is rather strongly so. The suture is channelled, the whorl 

 being excavated above it, narrowly horizontal and carinate close 

 below. There is a very slight median prominence of the columella, 

 hardly noticeable. The tip of the spire is turned in, nucleus 

 immersed. The aperture is rather oblique. 



Length 2.6, diam. 0.9 mm.; 6 whorls. 



T>T)e No. 3084, A. N. S. P. 



This species and the following one scarcely agree with the charac- 

 ters of Spiroclimax, and the channelled suture appears to remove 

 them from typical Odostomia. They seem to form a new subgenus 

 of Odostomia. As Doctor Bartsch has a general work on east x\meri- 

 can Pyramidellidce under way, we prefer to leave the final classifica- 

 tion in his able hands. 



A second specimen is more solid than the figured type but otherwise 

 similar. 

 Odostomia myrmecoon n. sp. 



The shell is structurally very similar to 0. santodomingensis, from 

 which it differs by the shorter, more obese outline and the slightly 

 sinuous columella. 



Length 2.25, diam. 1 mm.; 5| whorls. 



Type No. 3085, A. N. S. P. 



Odostomia (Eulimastoma) pyrgulopsis n. sp. 



The shell is openly perforate, long-conic, solid, marked with faint 

 gro"wth-lines only. (Nuclear whorls presumably immersed), the 

 first rounded above, turned in at the tip; following whorls fiat, 

 separated by a narrowly channelled suture, caused by the revolution 

 of the suture just below a peripheral angle; on the last two whorls 

 the suture descends more, leaving the peripheral angle, projecting 

 prominently. It weakens on the latter part of the last whorl. The 

 margin of the umbilical opening is rounded. Aperture is ovate. 

 Columella thin, concave, having a small, obliquely receding plait 

 above. 



Length 1.8, diam. 0.7 mm.; 6| whorls. 



Type No. 3092, A. N. S. P. 



There is considerable variation in the degree of descent of the last 

 two whorls, and the point where the more rapid descent begins. 



