4 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 64, 



from a large school without visibly reducing its size. Among the 

 Pantosteus were 50 examples of Gatostomus. Other catches seemed 

 to support this proportion. The 708 Pantosteus measured from 230 

 to 395 millimeters in length, the largest weighing 1-^ pounds, a real 

 giant among the hard-mouthed or mountain suckers. 



When in the water, P. virescens differs from other catostomids of 

 the rirer by its dark color, the posterior part of the body usually 

 appearing dense black in contrast with the lighter anterior region. 

 When the side is turned toward the sun, a flash of yeUow light appears, 

 and sometimes the white bellies and the broad mouths, with their enor- 

 mous lips, may be seen, the latter being so large that the edges are 

 visible on either side of the snout. 



When fresh from the water the color is a bright metallic yellow 

 on the sides; darker above and dead white below. The top of the 

 head is olive, lighter on the sides, brassy beneath the eyes. The lips 

 and throat are yellowish, the horny edges of the lips white. The 

 scale pockets on the dorsal surface have blackish borders, which are 

 wider on the posterior parts of the body, where they impart a dark 

 color to the entire surface. In some examples the dark borders are 

 very narrow, giving the fish a much lighter appearance. The inten- 

 sity of the color seemingly changes somewhat as the fish moves about 

 in the water. 



Two mountain suckers occur in the Bonneville system, P. vires- 

 cens and P. platyrhynchus, the latter appearing to be closely related 

 to P. lahontan of the Lahontan system of Nevada.^ 



P. 'platyrhynchus is a coarse scaled form, the lateral series num- 

 bering 78 to 89 rows. The snout is relatively short and rounded, 

 the papillae of the lips large, the caudal peduncle deep, and the caudal 

 fin short. 



Scales lateral series 78 79 80 81 82 83 84 85 86 87 88 89 



Number of specimens 1 7 5 9 19 14 12 14 7 8 3 1 



Scales before dorsal 39 40 41 42 43 44 45 46 47 48 



Number of specimens 1 3 8 5 28 24 18 9 2 2 



Scales above lateral line... 15 16 17 18 19 

 Number of specimens 7 32 51 7 3 



Scales below lateral line. __ 10 11 12 13 14 

 Number of specimens 5 26 38 23 8 



' It has been shown that P. generosus (Girard), referred by some authors to the Bonneville system, with- 

 out doubt came from the Colorado. (Proc. U. S. Nat. Mus., vol. 59, 1921, p. 27.) 



Minomus jarrovii Cope (Proc. Amer. Philos. Soc. Phila., 1874, p. 135) is not synonymous with either P. 

 virescens or P. platyrhynchus. The type of P. jarrovii is lost, the locality is in doubt, and while the descrip- 

 tion and figures (Wheeler's Explor. West of the 100th Merid., vol. 5, 1S75-76, p. 674, pi. 29, fig. 2, 2a) are 

 sufficient to show that the species is not synonymous with either of the Bonneville forms, the writer is not 

 able to refer them without doubt to another species. In the original description Cope refers to two speci- 

 mens "obtained by Messrs. Yarrow and Henshaw at Provo," while in the later paper these specimens are 

 ignored without explanation, and the name is applied to fishes from both the Colorado and Eio Grande 

 Elvers. It is possible that the type came from a tributary of one of these streams. 



