A DESCRIPTION OF THE GENUS DIMETKODON, COPE. 9 



rami of the lower jaws were apparently united by cartilage only, and the symphysis was 

 short. The vertebra: arc deeply biconcave. 



"Measurements from the type of this species are as follows: 



MM. 



Length of dentary bone 150 



Space occupied by teeth 180 



Extent of four anterior canlniform teeth 25 



Extent of twenty compressed teeth 105 



Height above jaw of second lower tooth 15 



Depth of dentary bone at symphysis 20 



Height of (-row n of compressed tooth 8 



Transverse diameter 4 



"This reptile was about sis feet in Length, and carnivorous inhabit. Its remains 

 are from Hie same Ideality ill New Mexico that yielded those of Nothodon." 

 This is probably one of the Clepsydropidce. 



" Ophiacodon minis, gen. et. s|>. nov. 



"A third genus of Reptiles allied to the hist described is indicated by various well- 

 preserved remains from the same locality. The teeth arc all carnivorous in type, conical 

 in form, and all art; similar. Those in the anterior part of the jaws are recurved, and in 

 general shape resemble those of Serpents. The rami of the lower jaws were united only 

 by cartilage. The vertebra are very deeply biconcave, and even perforate, and the infra- 

 central bones large. In the present species the teeth are nearly smooth, and somewhat 

 compressed. 



"The following measurements indicate the size of this reptile: 



MM. 



Extent of anterior sixteen teeth in dentary 75- 



Extent of anterior live lower teeth 20 p 



Height of crown of fourth lower tooth 10- 



Depth of lower jaw at symphysis 15- 



Extent of seven anterior maxillary teeth :',;;• 



Height of crown of first maxillary tooth !)• 



A atero-posterior diameter of crown ;;■ 



" This species was about as large as those described above, and is from the same 

 horizon in New Mexico. 



"Ophiacodon qrandis, sp. nov. 



"A second larger species of apparently the same genus is represented by portions of 

 the jaws, and teeth, and various parts of the skeleton. In this species the dentary bone 

 is angular at its anterior extremity, and triangular in section. Its external surface is 



A. 1'. s. — vol. xx. B. 



