28 PROCEEDINGS OF THE NATIONAL. MUSEUM vol.66 



Dimensions: Cotypes (N. S. Nat. Mus. Cat. No, 352642) measure: 

 (Larger cotype) altitude 4.3 mm.; greatest diameter, 1.8 mm. (est.) ; 

 length of ajDerture, 1.5 mm. ; (smaller cotype) altitude 3.2 mm. ; 

 greatest diameter 1.4 mm. ; length of aperture 1.3 mm. 



This new subspecies differs from Glyfliostoma amk-ta (Guppy). a 

 Bowden species, in having stronger nodules at the intersection of the 

 ribs and spirals and the two spirals in front of the anal fasciole of 

 more equal size. 



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

 south of Brasso railway station, Trinidad, British West Indies. 



GLYPHOSTOMA (?) ADDRINA, new species 



Plate 4, fig. 9 



Shell small, solid, semiporcellaneous, strongly axially and spirally 

 sculptured and consists of two and one-half nuclear and four post- 

 nuclear whorls. Whorls slightly inflated and rapidly enlarging; 

 suture appressed, flexuous, bordered below by a strong semikeeled 

 cord; anal fasciole wide, undulating, depressed, marked with in- 

 distinct spirals and arcuate growth lines. Nucleus large, smooth, 

 and inflated. Postnuclear whorls axially sculptured with about 

 seven strong rounded ribs, strongest below the anal fasciole, with 

 interspaces of about equal width; on the body whorl, the axials be- 

 come obsolete on reaching the canal. Spiral sculpture consists of, 

 aside from the subsutural cord, two on the earlier whorls and three 

 on the later whorls, cords which are a little stronger over the ribs 

 and separated by a little wider interspaces. On the back of the 

 body whorl, 14 spirals extend from the anal fasciole across the canal. 

 Aperture wide and well-rounded above. Anal sinus wide, deep, and 

 situated just anterior to the subsutural band; outer lip with a heavy 

 varix near and behind the margin. Inner lip consists of a thin wash 

 of callus with its lower external margin erect. Canal slightly ex- 

 panded and recurved at its anterior extremitj\ 



Dimensions: Type (U. S. Nat. Mus. Cat. No. 352643) measures: 

 Altitude 6.2 mm.; greatest diameter 2.5 mm.; length of aperture 

 2.5 mm. 



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

 of Brasso, Trinidad, British West Indies. 



Genus MICRODRILLIA Casey 



MICRODRILLIA TRINA, new species 



Plate 4, fig. 5 



Shell slender, rather solid, high spired, consisting of about four 

 nuclear and four postnuclear whorls. Apical whorl blunt, scarcely 

 inflated, and smooth; following nuclear whorls gradually enlarg- 



