Cope.] 44:0 [^i;ov. 15, 



Pariotichus brachyops Cope, Proceeds. Amer. Philos. Soc, 1878, p. 508. 

 The typical specimen is the only one that has come under my observa- 

 tion. Permian bed of Texas. 



Pariotichus iNcisrvus Cope. Ectocynodonincisivus Cope, Trans. Amer. 

 FMlos. Soc, 1886, p. 290, PL ii. Figs. 4, 5. 

 But one specimen has come under my observation ; it was found in the 

 Permian of Texas. 



Pariotichus ordinatus Cope. Ectocynodon ordinatus Cope, Proceeds. 

 Amer. Philos. Soc, 1878, p. 509. 

 The original specimen from the Permian of Texas is the onlj' one that I 

 have seen. 



Pariotichus isolomus Cope, sp. nov. 



Three nearly complete skulls represent this species in my collection. 

 In the most damaged of these the frontal and parietal bones are wanting ; 

 in another the skull is fractured so as to separate the maxillary and man- 

 dibular bones on one side so as to display the crowns of the teeth. 



As may be seen by the comparative key, this species is most nearly 

 allied to the P. aguti. The form of the skull is different and also the 

 sculpture. The skull is equilateral, and the posterior superior border is 

 nearly straight. The muzzle projects beyond the mouth border, so that 

 the incisor teeth are directed backwards at an angle of 45°. The nares 

 are separated by a space equal to their long diameter. The orbit is of 

 moderate size. Its anteroposterior diameter enters the lengths of the 

 skull anterior and posterior to it 1.75 times, being midway of the total 

 length. It exceeds by a little the interorbital width. The mandibular 

 ramus is robust, being a little deeper than wide, and the angle is small 

 and pinched, projecting behind the articul itionand in line with the rising 

 inferior border. The parietal foramen is well developed. 



In the sculpture of the superior surface of the skull the longitudinal 

 striae are more prominent than the transverse ones which connect them, 

 except on the muzzle, where they are about equally conspicuous. The 

 sculpture is finer and reticulate on the jugal and quadratojugal regions. 

 About a dozen longitudinal ridges between the orbits. Sculpture of man- 

 dible tubercular reticulate. 



Three teeth on each premaxillary bone, of graded lengths, the anterior 

 being much the larger. Posterior to these one or even two smaller teeth 

 may stand on the premaxillary. The large tooth of the maxillary is the 

 third from the premaxillary suture. At tlie fifth tooth the second longi- 

 tudinal row appears, and at the eighth tooth, the third. There are ten 

 teeth in line with the row which is external anteriorly, but posteriorly a 

 short row appears external to this one, which includes five teeth. The 

 crowns of the teeth of the two internal rows are low and compressed so as 

 to have a longitudinal edge. In the lower jaw there are three rows with 



