CLEPSYDEOPIDiE. 107 



R. 570*. .Fragment of a maxilla with broken teeth belonging either 

 to a species of Naosaurus or Dimetrodon ; from the reputed 

 Permian of Texas. The broken bases of six teeth remain, 

 and the crown of one germ-tooth is seen in alveolo. The 

 teeth accord in size and character with the hinder teeth of 

 Naosaurus claviger, figured by Cope in the ' Trans. Amer. 

 Phil. Soc' vol. xvi. pi. ii. fig. 1. Purchased, 1885. 



R. 564. Two portions of the neural spine of a vertebra; from the 

 reputed Permian of Texas. The smaller specimen, which 

 is evidently from near the distal extremity, exhibits the 

 subcylindrical section and the lateral tubercles, and thus 

 resembles the vertebra figured by Cope in the ' Trans. 

 Amer. Phil Soc' vol. xvi. pi. iii. fig. 3. Purchased, 1885. 



R. 564 a. Part of the neural arch and spine of a dorsal vertebra 

 apparently referable to this species ; from Texas. In the 

 contour of the transverse processes and the lower part of 

 the spine, this specimen approximates to the vertebra of 

 this species figured by Cope, he. cit., rather than to the 

 vertebra of iV. claviger represented in figs. 1, 2 of the same 

 plate. In the latter figure, the lower part of the spine is 

 represented as inclining backwards, and the lower hori- 

 zontal processes curving forwards, but in the present speci- 

 men both these directions are reversed. Purchased, 1885. 



Naosaurus claviger, Cope \ 



Larger than the preceding, with the distal extremities of the 

 neural spines of the vertebrae dilated and compressed, and the pro- 

 cesses large throughout the extent of the spine. 



It does not appear possible to distinguish the spines of this species 

 from those of N. microdus, Cope 2 , which is characterized by its 

 smaller teeth. 



Hab. North America (Texas). 



R. 564 b. A considerable portion of the distal half of the neural 

 spine of a dorsal vertebra ; from the reputed Permian of 

 Texas. Resembles the spine of the vertebra figured by 

 Cope in the < Trans. Amer. Phil. Soc' vol. xvi. pi. iii. 

 figs. 1, 2. Purchased, 1885. 



1 Amer. Nat. vol. xx. p. 545 (1886). 



2 See Trans. Amer. Phil. Soc. vol. xvi. p. 294. 



