BOTHREMYDIDA:. 



109 



The borders of the fourth and fifth neurals are 8 mm. thick. On the under side of each 

 is attacht the neural arch of the corresponding vertebra. The eighth neural was not developt 

 and the costals of the seventh and eighth pairs met at the midline. The ninth and tenth dorsal 

 vertebrae and the first sacral appear to have had their arches articulated with the inferior 

 surface of the seventh and eighth costals at their junction. The accompanying table gives the 

 dimensions of the three posterior neurals. 



The nuchal bone is urn-shaped, 90 mm. long, 43 mm. wide in front, 86 mm. across the 

 widest part, and 10 mm. thick. Its free border is acute. The first peripheral measures 58 mm. 



along its free border; the second, 53 mm. The first appears to 

 have been about 60 mm. high, measured at the suture with the 

 second. The free border of these two peripherals is subacute. 

 The greatest thickness of the second, at the distal end, is 12 mm. 

 On the right side most of the peripherals are wanting from the 

 second to the eighth (exclusive of both); all are missing behind the 

 second on the left side, except one, probably the sixth. The upper 

 and lower faces of this sixth meet at the acute free border at an 

 angle of about 45. This border is 45 mm. long and from this the bone rises 56 mm. to the 

 costals. In the restoration (fig. 101), this bone has been omitted from its supposed place. 

 The lower face of the bone, that proceeding to the plastron, is mostly missing. 



Neural. Length. Height. 



Yia.ioi.Taphrofphyslonginuchus. Carapace of the type. X}. The stippled areas 



represent the known bones. 



All of the peripherals have acute free borders. Of the eighth, that portion to which the 

 inguinal buttress was attacht is broken away. From the free border each of these bones 

 thickens on the under side to half its height, then becomes gradually thinner. 



The suprapygal is triangular, 62 mm. long and 60 mm. wide posteriorly. Evidently it 

 articulated on each side with the eleventh peripheral and medially with the pygal. 



