A DESCRIPTION OF THE GENUS DIMETRODON, COPE. 



2:'. 



" In a medium-sized specimen of D'mielrodon incisivus, where the vertebral body is 

 35 mm. in length, the elevation of the neural spine is 900 mm., or twenty and a half 

 times as great." The interclavicle is described as sternum and figured PL III, Fig. 5. 

 A posterior foot of Theropleura (spec. ?) is figured and described. 



Naosaurus differs from Dvmetrodon in the presence of transverse processes on the 

 neural spines. Portions of the skull and vertebra; of Naosaurus claviger are described 

 and figured (PI. II, Figs. 1-3; PI. Ill, Fig. 1). Vertebrse of Naosaurus cruciger and 

 N. mdcrodus are also figured (PI. til, Figs. 2 and 3). 



In 1887 Baur -'■-■'" gave the following diagram to express the relationship between 

 the Theromorpha, the other Reptiles and the Mammals: 



RHYNCHOCePHALlA 



~ i ~~ «... \\ 



AUROMAMMALIA "V * _ 



pROGANOSAURIA 



I 



Lydekker in 1890 21 describes some Pelycosaurian remains from the Permian of Texas 

 in his "Catalogue of the Fossil Eeptiliaand Amphibia in the British Museum," Part IV. 

 1. Pieces of the maxilla and neural spines of Naosaurus cruciger Cope. 2. Portions of 

 spines of Naosaurus claviger Cope, and of undetermined species of Naosaurus. 3. Two 

 dorsal vertebra. 1 and an intervening intercentrnni of Embolophorus spec. 4. Two dorsal 



