TESTUDINATA. 767 



were very numerous. My means of transportation being limited, I could 

 not collect a full series, but selected diagnostic bones from the best examples 

 for purposes of future study. Of the present individual I have the clavicle 

 ("episternal"), nuchal vertebral, several marginals, part of pectoral, and basal 

 part of half of posterior lobe of plastron. This is a large species, with the 

 marginal bones and edges of plastron thickened. The lip is produced, and 

 has parallel sides and a truncate free edge without denticulations. The 

 angle at which the borders would meet if produced, is obliquely cut off. 

 The inferior surface is deeply, openly grooved along the oblique line of the 

 gular dermal suture, and is excavated on the middle sutural line just ante- 

 rior to the mesosternum. The superior face of the lip slopes outwards, and 

 is, swollen laterally behind. The free marginal bones of the carapace are 

 not recurved at the margin. There is a projecting angle or point where the 

 dermal suture reaches the margin, which is immediately followed by a step- 

 like notch of little depth. 



The lateral suture of the gular scute on the upper side of the lip is 

 nearly parallel with the median suture, giving thus a paralellogramnic 

 outline. The nuchal scutum is long and narrow, and is not bounded on the 

 edge by mucros. The pectoral scutum is very narrow. 



Measurements. 



M. 



Length of lip on external edge 035 



Width of half of lip at base 046 



Thickness of lip at base 023 



Width of a free posterior marginal 082 



Length of a free posterior marginal 072 



Width of posterior lobe plastron at base.... 1^^ 



Anteroposterior width of pectoral scute 018 



Length of nuchal scute 040 



Width of nuchal scute 008 



Head of Horse Tail Creek, Colorado. 



TeSTUDO AMPHllHORAX Cope. 



Paleontological Bulletin No. 15, p. 6, August 50, 1673. Annual Report U. S. Geol. Surv. Terrs., 1873 



(1874), p. 511. 

 Plate LXI; fig. 4. 



Of this large species I have before me two specimens which display 

 the anterior lobe of the pla.stron, and probaby a third which does not in- 

 •clude that diagnostic part. 



