203 



M. 



Depth of the maxillary at the second condyle 095 



Depth of the maxillary at the twentieth tooth 0. 0'.;.", 



Diameter of the hase of the first premaxillary tooth 0. 01^ 



Diameter of the bases of five of the large maxillaries 0. 052 



Length of the dentary above 0. 270 



Depth at the second large tooth 0. 095 



Depth at the last tooth 0. 105 



Diameter of the base of the first large tooth 0.013 



Diameter of the base of the second large tooth 0. OiiO 



Length of the crown of the second large tooth 0. 050 



Length of the crown of the sixth tooth from behind 0. 025 



If of the same proportions as the P. molossus, the vertical diameter 

 of the head of this fish would be twenty-three inches. 



The type-specimen of P. lestrio was procured by Prof. B. F. Mudge, 

 of Manhattan, Kans., during his survey of 1872, near the Solomon River. 

 Professor Merrill's specimen was obtained from the same region. 



PORTHEUS MUDGEI, Cope. 



Represented by portions of the jaws, with vertebrae, of a single 

 individual, discovered by Prof. B. F. Mudge in Trego County, Kansas. 

 The prominent character is seen in the possession of four subequal teeth 

 in the premaxillary bone, which, therefore, presents a relatively long alveolar 

 border for their accommodation. The bone is also more massive than in 

 the other species, and is peculiarly thick on the free anterior edge. The 

 maxillary bone presents a similar character, and shows this fish to have 

 been the most robust species of the genus. The width of the superior 

 border of the maxillary is greater than in the others, although the vertical 

 extent of the bone is considerably less (see ' the measurements under 

 P. lestrio). There are five or six subequal large teeth behind an edentulous 

 space on the maxillary bone, while those on the posterior part of it are 

 small. The specimen is smaller than is usual in other species of the genus. 



Measurements. 



M. 



Width of the premaxillary bone 0. 054 



Elevation of the premaxillary bone above the first tooth 0. 060 



Thickness of the premaxillary bone at the middle 0. 021 



Depth of the maxillary at the condyle 0.057 



Depth of the maxillary at the fifth large tooth 0. 040 



Length of the bases of the five large teeth 0. 036 



Length of an anterior vertebra 0. 019 



Diameter, vertical 0. 031 



Diameter, transverse 0.031 



Occasionally, the P. lestrio exhibits one, or even two, minute additional 

 premaxillary teeth, but it exhibits but three large teeth in contradistinction 

 to the four large ones of the P. mudgei. 



