ART. 22 MIOCENE GASTROPODS AND SCAPHOPODS MANSFIELD 27 



and inflated. The sculpture on the first postnnclear whorl begins 

 with a faint arcuate intersutural axial and by two spirals on the 

 anterior part of the whorl; soon another spiral appears above giving 

 the first postnuclear whorl a canceilate sculpture. Axially sculp- 

 tured on the anterior whorls with about seven, small, arcuate riblets 

 extending with equal strength from the subsutural cord forward to 

 the suture, and separated by interspaces of more than twice their 

 width. On the last whorl the ribs are a little stronger and extend 

 down the steeply inclined basal slope to the canal. Spirally sculp- 

 tured on the earlier whorls by two and on the later whorl by three, 

 prominent cords overrunning the axials and extending from the 

 excavated anal fasciole forward to the suture. In addition to these 

 primary spirals, there are three or four secondary spirals on the 

 anal fasciole and two or three between the primary spirals. On the 

 back of the body whorl and over the canal, there are eleven primaiy 

 spirals with one or two interspiral threads. Aperture of about equal 

 length of spire; margin of outer lip broken away; anterior canal 

 not long and slightly arcuate. 



Dimensions: Type (U. S. Nat. Mus. Cat. No. 352641) measures: 

 Altitude 5.2 mm. ; greater diameter 2 mm. ; length of aperture 

 2.5 mm. 



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

 south of Brasso, Trinidad, British West Indies. 



GLYPHOSTOMA AMICTA RINTRIADA, new subspecies 



Plate 4, figs. 2, 3 



Shell small, solid, moderately slender, turrited, strongly axially 

 and spirally sculptured and consists of four nuclear and four post- 

 nuclear whorls; whorls moderately inflated with periphery at lower 

 one-half; suture loosely appressed. Apical whorl minute, smooth 

 and inflated; following nuclear whorls with a strong spiral keel 

 on the lower half of the whorl. Postnuclear whorls sculptured 

 with about ten arcuate riblets separated by interspaces about twice 

 their width, and extending from the suture behind the sloping anal 

 fasciole to succeeding suture ; on the body whorl, these axials extend 

 nearly across the canal. Spirally sculptured with two rather promi- 

 nent cords in front of the anal fasciole; the posterior one is a little 

 stronger, corresponding to the keel on the nuclear whorl ; the spirals 

 oAerrun the axials and are nodular at the intersection with the ribs : 

 anal fasciole with four or fi^-e smaller spiral threads. On the back 

 of the body whorl, about twelve rather uniform sized spirals extend 

 from the anal fasciole across the canal. Aperture rather long, with 

 a deep and Avide posterior sinus. Outer lip with a strong varix be- 

 hind, marked within with three or four lirae below the anal sinus. 

 Pillar with thin wash of callus. Siphonal canal short, recurved. 



