315 Dominican Fossils — Maury 151 



angles to the main axis of the shell; ribs strong, straight, slight- 

 ly narrower than their interspaces and ending at the periphery 

 of the last whorl, seventeen on the ultimate and penultimate 

 whorls; the spiral ornamentation consists of incised lines which 

 define broad, 'fiat bands, four to a volution, the three anterior 

 bands being equal, the fourth a little narrower; base of shell 

 smooth or with one or two incised spiral lines near the peri- 

 phery; aperture round ; columellar fold inconspicuous. Length 

 7.25, diameter 1 mm. 



Occasionally a specimen shows a broad varix as represented 

 in the species T. ambusta and T. catalinensis Dall and Bartsch,— 

 a feature distinguishing Mormula from Pyrgiscus. 



This dainty shell is named in honor of Miss Nannie Belle 

 Maury of Washington. 



Locality. — (Exp'd '16) Bluff 3, Cercado de Mao. 



Genus Odostomia Fleming 



Odostomia Sancti-Dominici, n. sp. 

 Plate 25, Figure 21 



Shell minute, polished, entirely smooth, sub-perforate, rather 

 thin; suture distinct; whorls five, their sides nearly straight, ex- 

 cept those of the body whorl which slope convexly to the round- 

 ed base; peritome discontinuous, outer lip thin, slightly pro- 

 duced anteriorly; aperture wide; fold of columella prominent. 

 Length of shell 2.5; of body whorl 1.50; of aperture .90; greatest 

 diameter 1.15mm. 



Locality. — (Exp'd '16) Bluff 3, Cercado de Mao. 



Odostomia yaguica, n. sp. 

 Plate 25, Figure 22 



Shell minute, with about seven whorls more or less flattened 

 except the last which is slightly convex; suture distinct, some- 

 what channeled by the beveled anterior edge of the volution ; base 

 of last whorl rounded; aperture ovate to quadrate; outer lip sim- 



