O. C. Marsh—Notice of New Fossil Reptiles. 411 
Height above jaw of second lower tooth ---..--- 16=° 
Depth of dentary bone at symphysis. ---------. 26° 
Height of crown of compressed tooth..-. ..-. -- 8: 
‘Transverse diameter... of o5.cedlcs ages 4° 
This reptile was about six feet in length, and carnivorous in 
habit. Its remains are from the same locality in New Mexico 
that yielded those of Nothodon. 
Ophiacodon mirus, gen. et sp. Nov. 
Extent of anterior sixteen teeth in dentary -- ----- aa 
Extent of anterior five lower teeth .-------------- : 
Height of crown of fourth lower tooth ----------- 10 
Dep lower jaw at sym PEE Ge + 
Extent of seven anterior maxillary teeth 33 
Height of crown of first maxillary tooth --.-.-.---- 9 
Antero-posterior diameter of crown --------.~----- 3 
This species was about as large as those described above, and 
is from the same geological horizon in New Mexico. 
Ophiacodon grandis, sp. nov. 
A second larger species of apparently the same genus is rep- 
resented 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 rugose, as in the Crocodiles. The crowns of the teeth 
are striate at the base, and the latter is furrowed vertically. 
The teeth are not so thickly set as in the smaller species, and 
the bases of the crowns are somewhat transverse. 
Measurements. 
Space occupied by ten anterior lower teeth ------- 140™™ 
Depth of lower jaw at symphysis - --------------- 129° 
Antero-posterior extent of symphysis .--.-------- 25° 
Depth of dentary bone below seventh tooth - ----- 30° 
Width of dentary at this point ------------------ 20° 
The present species was about ten feet in length, and the 
largest reptile yet found in this fauna. The remains are from 
New Mexico. 
Yale College, New Haven, April, 1878. 
