CONTRIBUTION TO THE PALEONTOLOGY OF TRINIDAD. 59 

 Geological horizon. — Upper Oligocene. Equivalent to the Chipolan stage of 



Florida 



Chione dalliana new species. Plate IX, Figure 16. 



Description. — Shell rather small for the genus, subcircular in outline; hinge 

 characters concealed by the matrix; inner edge of valves finely crenulate; sculp- 

 ture of regular, low concentric lamellae crossed by very fine, close-set, radial st ri© 

 which with the lamellae form a delicate cancellation over the entire surface* 

 anteriorly the radial sculpture strengthens, forming about seven well marked 

 plications. 



Length of shell 20, height 17, diameter approximately 8 mm. 



Remarks. — In general form and type of sculpture this species resembles Dr. 



Guppy's Chione walli from the Manzanilla beds of Trinidad; but it is at once 



distinguished from that species and from the other related forms described in 



this report by the very characteristic anterior radial plications. 



The shell is dedicated to Dr. W. H. Dall, of the National Museum, Wash- 

 ington. 



Locality. — Along the shore 1000 feet west of the pier at Brighton, Trinidad, 

 in impure asphalt. 



Geological horizon. — Upper Oligocene. About equivalent to the Chipola 

 stage of Florida. 



Chione guppyana new species. Plate IX, Figure 19. 



Description. — Shell of moderate size, suborbicular, slightly obtusely pointed 

 at the posterior end, sculpture of same general type as C. veatchiana,— that is, 

 finely and delicately cancellated by the intersections of radiating threads with 

 somewhat less pronounced, concentric lamellae; interior margin finely and sharply 

 crenate; pallial sinus quite deep and obtusely triangular; hinge characters as 

 shown in the drawing. 



Length of shell 19, height 16 mm. 



Remarks. — This species is readily distinguished from C. veatchiana by its 



more circular outline and the striking differences in the form of the pallial sinus 



which in veatchiana is typical, but in guppyana rather deep and broad for the 



genus. From C. dalliana this species is distinguished by the absence of the 



characteristic seven or eight strong radial plications on the anterior end of that 

 shell. 



This species is dedicated to Dr. R. J. Lechmere Guppy, of Port of Spain, 

 Trinidad. 



Locality .—Along the shore 700 feet east of the Brighton pier, Trinidad, in 

 impure asphalt. 



Geological horizon. — Upper Oligocene. About equivalent to the Chipolan 

 stage of Florida. 



