50 PROCEEDINGS OF THE NATIONAL MUSEUM vol.66 



Dimensions: Figured specimen (U. S. Nat. Mus. Cat. No. 352686) 

 measures: Altitude 29 mm.; maximum diameter 19 nun. 



Locality of figured specimen: Station 9219. Guaico-Tamana 

 Road, 2 chains east of mile 13 from junction with Eastern Main 

 Road. 



The species is closely related to Modulus w'dcoxil Dall from the 

 Chipola marl member of the Alum Bluff formation, Florida, but 

 it differs mainly from Dall's species in having stronger spiral 

 sculpture and lacking the blunt duplex and undulating carina at the 

 shoulder of the body whorl. When compared with M. hasileus 

 (Guppy) from the Bowden marls of Jamaica, that species is found to 

 have much weaker spirals over the middle part of the whorl and a 

 proportionally^ heavier carina on the basal whorl. 



Occurrence. — Lower or middle Miocene : Nariva County, Charuma 

 Ward. Machapoorie Quarry. 



Genus CAECUM Fleming 



CAECUM PROPEREGULARE, new species 



Plate 8, fig. 6 



Shell small, solid, strongly curved, moderately tapering; periphery 

 at anterior one-fifth of length; anterior extremity smooth and con- 

 tracted, sloping forward from the periphery. Sculpture of (about 

 24) rounded, close-set threads, separated by shallow stria; posterior 

 annulation 'a little wider and more prominent and marginating the 

 posterior end. Plug not extending much above the margin of the 

 shell; mucro small, situated at the margin on the convex side. 



Dimensions: Type (U. S. Nat. Mus. Cat. No. 352675) measures: 

 Length 1.5 mm. : diameter of anterior end 0.3 mm. ; diameter of pos- 

 terior end 0.2 mm. 



The new species belongs to the group of Caecum regulare Carpen- 

 ter, but that species has sharper spiral annulations. It more closely 

 resembles an unpublished new species from the Shoal River marl 

 member of the Alum Bluff formation of Florida. 



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

 County, Montserrat Ward, 1 mile south of Brasso Station. 



Genus VERMICULARIA Lamarck 



VERMICULARIA, species 



There, are specimens of the Genus Vermicularia from Springvale, 

 near Couva, station 9195, that resemble Vermictdarna ehuriuus 

 Reeve, a Recent species of the west coast geographically ranging 

 from San Diego, Calif., to Panama, but the material at hand is 

 hardly adequate for specific determination. 



