576 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.49. 



not much, if any, larger than those of the row immediately below. 

 Those of the succeeding rows above the lateral line rapidly and some- 

 what regularly grow larger and more rounded in outline, until on the 

 median part of the back they are much larger than any on the caudal 

 peduncle. The hps have a prominent horny sheath. The skuU is 

 thick, the edges of the parietals and frontals imiting in a firm suture, 

 thus completely obUterating the fontanelle. 



Of the other species, P. arizonae has a skull of similar structure, 

 and very large scales above the lateral Une. A comparison of the 

 type of P. arizonae and cotypes of C. clarTci indicates that they are 

 specimens of the same species. The scales in the lateral series are 

 found to number from 62 to 75, the series between lateral line and 

 back 7 to 9, between lateral line and ventrals 11 to 14, between occiput 

 and dorsal fin 15 to 17. 



Specimens from Beaver Creek. 



Lateral line 69 68 70 66 66 70 62 64 



Above lateral line 98987979 



Below lateral line 10 10 10 11 10 10 11 9 



Beforedorsal 16 15 16 17 17 17 15 17 



Type and paratype P. arizonae. 



Lateral line 67 69 



Above lateral line 8 8 



Below lateral line 11 H 



Before dorsal 16 17 



Cotypes of C. clarki. 



Lateral line 65 66 



Above lateral line 8 9 



Below lateral line 11 10 



Before dorsal. : 17 17 



There is no material difference in the form of the body, proportions 

 of various parts, fin rays, etc., as the following table of measurements 

 will indicate : 



