135 



[Cope 



Diameters of nostril 



Diameters of orbit 



interorbital space is gentlj' convex, and is wider than tlie diameter of 

 the eye, bnt how much wider the state of the specimen leaves un- 

 certain. The jugal bone is quite narrow below the orbit, its vertical 

 diameter equaling two-fifths that of the latter. The surface of the 

 cranium is rather minutely wrinkled, and does not display the grooves 

 seen in the Diadectes latibuccatus. The tabular bone forms a rounded 

 and narrowed cap of the posterolateral angle of the skull, and is 

 much less prominent than in the genus Chilonyx, but more so than in 

 Diadectes, where it is not distinguishable by suture. 



Measurements. mm. 



Total length of cranium from premaxillary border to 



OS tabulare inclusive 384 



vertical 25 



transverse 33 



Distance from nostril to orbit 78 



vertical 53 



transverse 54 



Interorbital width (posterior to middle) 70 



Length of dental series (chord) 150 



! longitudinal 15 



anteroposterior 7 



transverse 10 



f longitudinal 13 



Diameters m. xii } anteroposterior 6.5 



' transverse 13 



! longitudinal 10 



anteroposterior 5 



transverse 8.5 



The dimensions of this skull are equal to those of the Diadectes 

 ;phaseolinus, and about one-fourth larger than those of the D. latibuccatus. 

 The bones of the cranium are thinner and lighter than those of any 

 other species of the famil}' that has come under my observation. 



PARIOTICHID^. 

 Pariotichus adxjncus, sp. nov. 



Represented by a cranium of which the muzzle and right side, with 

 the right ramus of the mandible, are preserved, together with some other 

 fragments, of one individual ; and by a distorted cranium of a second. 



The species is intermediate in size and characters between the type of 

 the genus P. brachyops and the larger P. agiiti, besides presenting a 

 number of peculiarities of its own. The elongate maxillary teeth are 

 graded in size to the smaller, and the sixteenth from behind, the largest, 



