BAENID^. 



75 



width at its base is 125 mm.; its length in the middle line is 90 mm. At a point half-way 

 between the tip and the base the width is 88 mm. The width of the bridge is 145 mm. The 

 hinder lobe of the plastron is broadly tongue-shaped, with the tip truncated and broadly 

 notcht. At its base this lobe is 125 mm. wide; and in the midhne it is 100 mm. long. 



The sutures between the various bones of the shell are usually very obscure, but most of 

 them are determinable. The limits of the neurals (fig. 57) are somewhat conjectural. Those 

 between the costals and the peripherals run probably close to the sulcus between the costal and 

 peripheral bones. The most anterior peripherals, however, rise above this sulcus. 



The sutures of the plastron are hard to trace. Only the general course of those limiting the 

 entoplastron and the epiplastra is discernible. The sutures between the bones of the plastron 

 and the peripherals lie about 44 mm., mesiad of the shell margin. At a point about 40 mm. 

 behind the axillary notch is observed the suture between the hyoplastron and the mesoplastron. 

 Its course is inward and somewhat backward to a point in the midline about 66 mm. behind the 

 line joining the axillary notches. Another distinct suture may be observed about 38 mm. in 

 front of the inguinal notch on the left side. It can be traced toward the midline, where it 

 becomes obscure. This suture is that between the mesoplastron and the hypoplastron. Thus 

 the inner ends of the mesoplastron are about 24 mm. wide. 



57- 



FlGS. 57 AND 58. Baena clara. Type. 

 57. Carapace. 58. Plastron. 



At a point in the midline about 45 mm. behind a line joining the inguinal notches the 

 sutures between the hypoplastra and the xiphiplastra are seen running nearly directly outward. 



The impressions defining the epidermal scutes are usually very distinct. The sides of the 

 vertebral scutes are bracket-shaped. The lateral boundaries of the first vertebral run nearly 

 parallel and the scute is nearly as wide in front as it is behind. It has a length of 56 mm., a 

 posterior breadth of 63 mm., and an anterior breadth of about 58 mm. The lateral sulcus 

 on the left side is deflected somewhat toward the right side as it passes forward. It is possible 

 that an accessory lateral scute is cut off from the front of the usual first lateral scute and lies 

 to the left of the first vertebral. It is provisionally represented in the diagram above. 



