^RT. 22 MIOCEXE GASTROPODS AND SCAPHOPODS MANSFIELD 19 



DRILLIA TRIDADINA, new species 



Plate 3, fig. 11 



Shell small, stout, solid, glazed, strongly constricted at the suture, 

 strongly axiall}" sculptured and consists of two and one-half nuclear 

 and six and one-half postnuclear whorls. Suture appressed and 

 wavy. Nucleus rather small, glassy, smooth with whorls moderately 

 inflated between the grooved sutures. Postnuclear whorls con- 

 stricted by a low-lying, flat, wide band bordered anteriorly by a 

 microscopic stria and posteriorly by the suture. Axial sculpture con- 

 sists of strong, rather sharp, slightly protractive ribs (10 on the 

 penultimate whorl), extending from the anal fasciole forward to 

 the suture. Spiral sculpture — only visible on the anterior whorls — 

 faint, consisting of five or six wide-spaced, shallow striae, separated 

 by wide, nearly flat areas. The posterior one-half of the canal is 

 sculptured with three spiral bands and subdued axials forming a 

 reticidate ornamentation; anteriorly, the ribs become obsolete and 

 the sculpture consists of fine, unequally spaced spirals forming the 

 siphonal fasciole. Margin of outer lip broken away. Inner lip 

 consists of a thin callus and externally loosely overlaps the pillar. 

 Canal short and dextrally curved. 



Dimensions: Type (U. S. Nat. Mus. Cat. No. 352632) measures: 

 Altitude 7.0 mm. ; gi-eatest diameter 2.5 mm. 



The new species here described is characterized by its cingulum 

 situated anterior to the suture, strong axials, and faint spirals. 



Occurrence. — Middle or lower Miocene : In flood-wash, 1 mile 

 south of Brasso, Trinidad, British West Indies. 



DRILLIA DADITRINA, new species 



Plate 3, figs. 1, 5 



Shell rather slender, solid, semiporcellaneous, strongly axially 

 sculptured, with one and one-half nuclear and six moderately inflated 

 postnuclear whorls; anal fasciole wide, undulating, without spiral 

 striae ; suture narrow and shallowly grooved. Nuclear whorls smooth, 

 inflated, of medium size. Postnuclear whorls axially sculptured with 

 strong, broad, rounded, nearly vertical ribs (six on the penultimate 

 whorl) extending across the whorl from the subsutirral cord forward 

 to the suture, suppressed across the anal fasciole and strong over the 

 middle of the whorl; on the last whorl, the axials terminate on 

 reaching the canal. Spirally sculptured on the earlier whorls by 

 two, strong, rather wnde-spaced, paired cords, the posterior one 

 bordering the anal fasciole — both overrunning the axials; on the 

 later whorls an intermediate cord of equal strength comes in ; in ad- 

 dition to these cords, there is another cord in front of and marginat- 



