913] The Ottawa Naturalist. 61 



Cope, from the Oligocene of Colorado. 



Regarding the present specimen as representing an un- 



deseribed species of Testudo, the name prceextans, having refer- 

 ence to the marked prominence and size of the epiplastral lip, 

 is here proposed for the species with this specimen (Cat. No. 8401) 

 as the type. 



In plates I and II, shewing the carapace and plastron 

 respectively, the sutures between the bones and the sulci marking 

 the boundaries of the scutes are well shewn and can be readily 

 traced. 



Of the specimens belonging to the collection of turtles from 

 the Oligocene of Sage creek, mentioned in the opening paragraph 

 of this paper, and regarded as referable to Stylemys nebrascensis, 

 Leidv, one in particular is of interest. 



In this specimen certain abnormalities occur in the carapace 

 which are considered of sufficient importance to warrant descrip- 

 tion. The plastron appears to be quite normal. 



The shell as a wdiole has been somewhat distorted. A 

 horizontal pressure on the left side has caused the left costal 

 bones to be unduly bent down and the bridge peripherals to be 

 incurved below\ The plastron has been moved to the right and 

 pressed upward along its longitudinal midline. Otherwise the 

 specimen is splendidly preserved. The carapace is 276 mm. 

 long and 215 mm. broad in its present state; its highest central 

 point is about 119 mm. above the lower edge of the peripherals 

 near the bridge. Plates III and IV, reproduced from photos 

 graphs, shew the carapace and plastron with the bones and scute- 

 clearlv defined and reference need only be made here to the 

 divergence of the carapace from the normal type of structure. 



In the carapace there are seven costal scutes on each side 

 instead of the usual four, and an additional vertebral scute 

 between the fourth and the broad posterior one. Also an 

 accessory bone occurs between the eighth neural and the first 

 suprapygal, and there is a ninth pair of costal bones. 



With the exception of the above structural peculiarities 

 the carapace conforms to the usual type of 5. nebrascensis. The 

 first neural bone is of an elongated quadrangular 

 form, and the succeeding ones are hexagonal. The costal bones 

 shew a slight differentiation in distal breadth. The marginal 

 bones reach the usual number of eleven on each side, as do also 

 the marginal scutes. There are two suprapygal bones, of which 

 the first is bifurcated behind; the second is diamond shaped and 

 much broader than long. The nuchal scute is extremely narrow. 

 The supracaudal scute is undivided. These characters are normal 

 to the species. 



