180 Annals of the Carnegie Museum. 



The skull, especially the facial portion, is short. The malar por- 

 tion of the zygomatic arch is heavy and its lower border has two 

 rounded angles. If the post-orbital processes of the jugal and frontal 

 united at all they must have formed a very narrow bridge behind the 

 orbit. The squamosal portion of the zygomatic arch rises quite ab- 

 ruptly from a little behind the malar. On the postero-inferior portion 

 of this ascending portion is a long elliptical rugose convexity. 



The meatus aiidiforius externus is peculiar. It opens backward, out- 

 ward and upward, the outer portion being a short, large tube. Inward 

 from this it is wedge-shaped, something like that in Foafrephes, but 

 in this specimen the apex is turned forward and fits closely against the 

 horizontal portion of the zygoma and the posterior portion of the 

 post-glenoid process. It is possible that in one of these specimens 

 the meatus is slightly displaced. There undoubtedly was a tympanic 

 bulla, but it is lost. The paroccipital process has much the same 

 form as in Poatreplies, but is not so broad. The occipital condyles 

 and the foramen magnum are large. The orbit is large. The infra- 

 orbital foramen opens above P^. 



The portion of the mandible preserved is much like that of Eporeo- 

 don. The lower border of the mandible slopes gradually backward to 

 the angle. The masseteric fossa does not extend so far down. 



Measurements. y^^ 



Length of upper molat-premolar series 88 



Length of premolar series 43 



Length of molar series 45 



Depth of zygomatic arch under orbit 20 



Width of auditory meatus antero-posterior ... 20 



Width of paroccipital process 21 



Width of occipital condyles 43 



Width of foiamen magnum 21 



Depth of mandible under anterior portion of third molar 38 



The name of this species is given iii honor of my friend. Prof. 

 F. D. Smith, who so kindly gave aid and encouragement in the col- 

 lecting of fossils from these beds. 



Madison Valley Beds. 

 PISCES. 

 No. 857. Fig. 20. 

 The only evidence of the occurrence of fish remains in this forma- 

 tion is the centrum of one of the anterior vertebrae. It represents a 



