TESTUDINIDA:. 



423 



The palatal region (fig. 553) is highly vaulted, the median fossa having a width ot 23 mm. 

 The narrowest portion of the pterygoids is also 23 mm. wide. On the outer border of each 

 pterygoid is a distinct ectopterygoid process. The vomer is well archt upward, and is traverst 

 by a longitudinal ridge, which is sharp in front, but rounded behind. The masticatory surface 

 of the maxilla presents 2 longitudinal ridges and 2 deep grooves. The outer and principal 

 ridge is separated from the descending cutting-border of the jaw by the wider groove. This 

 ridge is received in the groove of the mandible. The ridge is sharp, slightly tootht, and runs 

 forward and inward to the premaxilla, then directly forward on the latter bone to its cutting- 

 edge. The inner ridge is low, flat, and rather broad, especially behind. It occupies the inner 



552. 



FIGS. 552 AND 553. Testudo oshorniana. Skull of type. X . 

 552. Upper surface. 553. Lower surface. 



border of the maxilla. There is no ridge occupying the midline along the symphysis of the 

 premaxillae; hence this species can not be regarded as a Gopherus. The masticatory ridges 

 of the right and left sides are separated by a deep longitudinal groove. This is interrupted only 

 by a rough eminence on the hinder ends of the premaxillae. The cutting-edge of the maxilla 

 descends much below the roof of the mouth. 



In many respects this skull resembles that of T. gilberti; but, as shown under that species, 

 T. osborniana has a much broader iugal arch, a more elongated otic region, a squamosal region 

 less comprest laterally, and a more heavily constructed skull. 



The carapace is high and swollen, resembling in general form the shell of T. radiata, of 

 Madagascar. The following table presents the dimensions of the carapace and plastron. 



Millimeters. 



Total length of carapace 775 



Width of carapace 555 



Height of shell 430 



Length of plastron 710 



Millimeters. 



Width of anterior lobe 425 



Length of anterior lobe 2 TO 



Width of posterior lobe 355 



Length of posterior lobe 180 



The carapace (plate 72; text-figs. 555, 556, 557) is truncated in front, broadly rounded 

 behind. The sides overhang the borders of the plastron. The nuchal and the anterior periph- 

 erals are flared upward. The ninth and tenth peripherals are also somewhat flared; the 

 eleventh and the pygal are nearly vertical. The free borders of the carapace, both in front and 

 behind, are acute. 



