TESTUDINID. 423 
The palatal region (fig. 553) is highly vaulted, the median fossa having a width of 23 mm. 
The narrowest portion of the pterygoids is also 23 mm. wide. On the outer border of each 
pterygoid 1s a distinct ectopterygoid process. The vomer 1s 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 1s 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 
Fics. 552 AND 553-—T estudo oshorniana. Skull of type. 2. 
552. Upper surface. 553- Lower surface. 
border of the maxilla. There is no ridge occupying the midline along the symphysis of the 
premaxilla; 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 premaxilla. The cutting-edge of the maxilla 
descends much below the roof of the mouth. 
In many respects this skull resembles that of 7. gilbert:; but, as shown under that species, 
T. oshorniana has a much broader jugal 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 7. radiata, of 
Madagascar. The following table presents the dimensions of the carapace and plastron. 
Millimeters. Millimeters. 
Total length of carapace... . 775 Width of anterior lobe 425 
Width of carapace. 555 Length of anterior lobe 210 
Height of shell... . -. 430 Width of posterior lobe 355 
Length of plastron : 710 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. 
