180 CONTRIBUTIONS TO NORTH AMERICAN ICnTIIYOLOGY — III. 

 Specimens in Unitcrl Slates Xulional Museum. 



Number. 



12914 

 l.->783 

 15791 

 20475 



Locality. 



Collector. 



Zuui,N.Mox 



Arizoua 



Snake River, Idaho 



Newberry. 

 Yarrow & Ilenshuu-. 

 C. G. Newberry. 

 F. V. Hayden. 



Genus PANTOSTEUS Cope. 



2Iinomiis Cope, U. S. Geol. Surv. Wyoming, 1870, 434 (187-2). (Not of Ginird.) 

 I'antosteus Cope, Lieut. Wheeler's Expl. W. 100th Mer. v, G73, 187G. 

 Catostomus, Acomus ct Minomus sp. Gin.vRD. 



Type, Alinomus plalyrhynchns Cope. 



Etymology, ttuv, all ; oa-t:ov, bouc (from the closing of the fontanelle by bone). 



Dead moderate or rather small, 4 tD 5 times in length of body, ll.ittish 

 and rather broad above, anteriorly somewhat pointed ; eye rather small, 

 usually behind the middle of the head : suborbital bones narrow, as in 

 Catostomiifi ; bones of hea^l rather thick, the two paiietal bones firmly 

 united, entirely obliterating the fontanelle. 



■Mouth rather largo, entirely inferior; each jaw with a more or less, 

 developed cartilaginous sheath, separable in alcohol, essentially as in 

 Chondrostoma, Acrochiliis, and related genera; upper lip broad, i)apillose, 

 with a rather broad, free margin, and several series of tubercles ; hnver 

 lip largely developed, with an extensive free margin deeply incised 

 behind, but less so than in Catostomun. Pharyngeal bones and teeth 

 e.sseutially as in Catostoimis. Isthmus quite broad. 



Body generally elongate, subterete, and little compressed. 



Scales quite small, from 80 to 105 in the course of the lateral line, 

 and 30 to 33 in a cross series between dorsal and ventrals, usually more 

 or less reduced in size and crowded forward, as in Catostomtis ; lateral 

 line well developed, straightish. 



Fins generally rather small ; first ray of dorsal usually about iniilway 

 of body, its rays few, 9 to 12 in number; ventrals inserted rather under 

 l)osterior part of dorsal, their rays 10 or 9 ; anal short and high, with 

 7 develop<(l rays; caudal rather shallow, emarginate ; pectorals well 

 developed : air-bladder w ith two chambers. 



The characters of rmitostcus are essentially those of Ca/o.s/o;///w, except 

 that the fontanelle is obliterated. The usual .scale formula is interme* 



