293 



border which joined its fellow of the other side missing, so that it is impossible to determine 

 accurately the width of the anterior lip of the plastron. However, this bone has been used 

 in making the restoration of the front of the plastron, as seen in fig. 361. Plate 45, fig. 5, and 

 text-fig. 362 show this bone as seen from below. It resembles closely the same bone in C. 

 guttata, except that its upper side was not so deeply excavated as in the latter species. Accord- 

 ing to the restoration the lip had a breadth of about 34 mm. 



The free borders of the epiplastron are subacute. Seen from the side, this border runs 

 forward to the gulo-humeral sulcus and then turns rather abruptly downward, forward and 

 inward. From the acute edge the bone thickens rapidly, until a thickness of 7 mm. is attained. 

 The gulo-humeral sulcus probably continued backward on the entoplastron. 



A piece of the thickened border of the xiphiplastron of this specimen is present. It extends 

 from the junction with the hyoplastron to just behind the femoro-anal sulcus. Most of the 

 free edge is broken away, but enough remains to show that it was acute. It thickens gradually 

 until, at the inner border of the surface above, which was covered with horny skin, the thick- 

 ness is 6 mm. The femoro-anal sulcus comes to the free edge 19 mm. behind the anterior end 

 of the bone. 



Plate 45, fig. 6, and text-fig. 363 present a view of the first right peripheral, both from above 

 and from the right-hand edge, which joined the second peripheral. The left-hand border 



361. 



363- 



FIGS. 361-365. Clemmys hesperia. Portions of shell. Xl. 



361. Left hyoplastron of type. No. 2219 Univ. California. The epiplastron is restored. 



362. Portion of right epiplastron. Xl. No. 2179 Univ. California. 



363. First right peripheral, with section (a). XL No. 2179 Univ. California. 



364. Probable ninth peripheral, with a section (a). No. 2179 Univ. California. 



365. Section of free border of hypoplastron. No. 5527 Univ. California. 



joined the nuchal. The first peripheral resembles closely that of C. guttata. It will be observed 

 that the outer anterior angle of the first vertebral scute extends outward on the bone here 

 described and comes into contact with the second marginal scute. We have the same arrange- 

 ment here that we find in C. leprosa, as shown by fig. 30, page 102, of Boulenger's Catalogue 

 of Chelonians. This indicates that the first vertebral scute was broader than it is in C. guttata. 

 The peripheral mentioned above, probably the ninth of the right side, resembles somewhat 

 that represented by plate 45, fig. 7, and text-fig. 364; but it is shorter antero-posteriorly and 

 higher, the fore-and-aft dimension being 15 mm., the height 19 mm. The longitudinal sulcus 

 runs closer to the upper border than in fig. 364. The figure just referred to presents a view of 

 the left ninth peripheral of an individual somewhat larger than the one just described. It 

 is part of a lot numbered 552, from either the Mascall or the Rattlesnake beds. Fig. 364 

 shows the upper surface and the anterior end of the bone. Accompanying this bone there is 

 the hinder outer angle of the hypoplastron, extending from the suture with the xiphiplastron 

 to the inguinal buttress. A view of a section of the bone near the xiphiplastral suture is 



