No. 1747. 



DESCRIPTIONS <)l' \i:\\ FOSSIL TURTLES II \Y 



309 



the right and the left hyoplastra, the greater portion of the left first 

 costal bone, and parts of three other costals. All of these hones, 

 except one of the costals, are illustrated here (Plate 10, figs. 1 3) by 

 reproductions of photographs.. The inc/vidual was not a young one, 

 inasmuch as all the bones are closely sutured together. The hones, 

 too, arc relatively thick and solid. Fig. 1 presents a restoration of 

 the plastron. Only the stippled portions are represented by hones 

 actually known. Plate 10, fig. 1, represents the same hones placed in 

 their natural relations. 



The width of the hinder lobe is only 51 nun. ; but this was probably 

 narrow in comparison with the whole width of the shell, which was prob- 

 ably about 110 mm. wide. 

 The right hypoplastron 

 is incomplete, since the 

 outer anterior border and 

 a part of the buttress are 

 missing. Its length is 25 

 mm.; its thickness on 

 the midline and on a lino 

 between the two buttresses 

 is (') mm. ; where it joined 

 the xiphiplastron, 3.5 mm. 

 On the upper surface is a 

 notch for a process of the 

 xiphiplastron. But little 

 of the subacute free border 

 is preserved. Evidently 

 the buttress was strong, 

 and it probably ascended 

 to the lower ends of the cos- 

 tals. The right hypoplas- 

 tron is somewhat longer 

 than the left and came into 

 contact with the inner end 



of the left mesoplastron. The hitter hone is 12 mm. wide near the 

 inner end. How long it was transversely to the body can not he 

 accurately determined, nor its distal width. It is (> mm. thick at 

 the front edge. It is remarkable how near to the inguinal notches 

 the hypo-xiphiplastral suture is placed. The mesoplastron of the 

 Leftside was considerably wider at the inner end than was the one of 

 the right side, inasmuch as it came into contact with the right hyo- 

 plastron a distance of 3 or 4 mm., and probably for a, short distance 

 with the right hyoplastron. 



The right hyoplastron lacks the outer and the anterior portions. 

 It is thick behind, to correspond with the mesoplastron. In the ante- 



FlG. L— COMPSEMYS PARVA. X 5- RESTORATION OF PL \STIioN. 

 THE STIPPLED AREAS INDICATE THE PARTS ACT! ALLY KNOWN. 



