G. H. Wieland — Upper Cretaceous Turtles. 123 



the median line is by digitation — not by suture, with a large 

 assymmetric and sub-oval median foramen at the hyo-hypoplas- 

 tral, and a much smaller, at the hypo-xiphiplastral junction (f, 

 f, figure 4). There are also small lateral foramina of crescen- 

 tic outline between the 5th marginal and the hyo- and hypo- 

 plastron, as may be seen in Plate VIII. 



The manner of the bridge connection with the carapace is 

 of interest. Although truly dactylosternal, there are distinct 

 suggestions of a former cleidosternal (closely interlocking 

 suture) union as in Adocus. The axial and inguinal limbs or 

 buttresses project into sockets in the posterior end of the 2d 

 and the anterior end of the 8th marginals. 



(a) 



Figure 6. — Osteopygis Gibbi type, x .£. 



(a) Left humerus, dorsal view. 



(6) Eight femur, dorsal view, with fibular trochanter shown in dotted out- 

 line. 



Cope speaks several times of a large rib cavity in the second 

 marginal. But such cannot be present in any species of the 

 genus Osteopygis. The second, or first large rib, projects with 

 strong backward* curvature into a long claw-like depression in 

 the third marginal. The large pit in the second marginal 

 appears to be a remnant of a former hollow beneath the axial 

 buttress, and must serve mainly for muscular attachment, since 

 only the lower edge is occupied by the end of the hyoplastral 

 peduncle. The dactylations between the buttresses are short 

 and robust. Those of the hyoplastron project against the 

 lower inner border of the 3d and 4th marginals, which are 

 pitted for their reception. Those of the hypoplastron project 

 similarly against the 6th and 7th marginals. The hypoplastral 



