30. CATOSTOMID.E — PANTOSTEUS. 121 



giuuing in front of ventrals and ending just before anal, of about 30 rays, 

 strongly falcate in front, the first and second developed rays in length 

 more than half the length of the base of the fin, the raj's rapidly short- 

 ened to about the eighth, the length of the remaining rays being nearly 

 uniform and all short. Caudal fin large, widely forked, the lobes jibont 

 equal. Anal fin quite small, low, of 7 or 8 developed rays, scaly at base. 

 Ventrals moderat e, with 10 rays. Pectorals elongate, somewhat fal 

 cate. Sexual i^eculiarities somewhat marked ; the males in spring with 

 black pigment; the head then covered with small tubercles. Air-blad- 

 der with two chambers, the anterior short, the posterior elongate. One 

 species known, {/.u/.hj:;, round; ).£-Tdg, slender. "The name means 

 small round mouth." — Rajinesquc.) 



122. C cIoaig'a.tQES (Le Sueur) Ag. — Blade Horse; Gourd-seed Suvlicr ; Missouri 

 Sucker; Suckerel. 



Depth 4-5 in length ; head C-8i. Eye small, C-7 in length of head. 



Longest dorsal rays a little longer than head. Pectorals rather longer 



than head. Dorsal rays 30 ; anal 7 or 8 ; scales 9-50-7. Coloration very 



dark, the males almost black. Size large. Length of adult 1 |-2i feet. 



Mississippi Valley; rather common. A singular and interesting fish. 



(Catostomus elonffatus Lie &nenr, Jouru. Acad. Nat. Sci. Pliila. 1817, 103: Sclerogna- 

 ihus clonciatus Guutlier, vii, 23; Jordan, ]. c. 189.) 



63.— PAWT©§TEUS Cope. 

 Hard-headed SucJcers. 



(Cope, Lieut. Wheeler's Exi)l. W. lOOth Mer. v, G73, 187(5 : type Minomus pJatiirliiinclinfi 

 Cope.) 



Head moderate or rather small, 4-5 times in length of body, llattish 

 and rather broad above, anteriorly somewhat pointed. Ej-e rather 

 small, usually behind the middle of the head. Suborbital bones narrow, 

 as in CatoHtomus. Bones of head rather thick, the two i)arietal bones 

 firmly united, entirely obliterating the fontanelle. Mouth rather large, 

 entirely inferior ; each jaw with a more or less developed cartilaginous 

 sheath, separable in alcohol, essentially as in CJiondrostoma, Aeroehilus, 

 and related genera. Upi)er lip broad, papillose, witli a rather broad, 

 free margin and 2 or more series of tubercles. Lower lii> largely devel- 

 oped, with an extensive free margin deeply incised behind, but less so 

 than in Catostomus. Pharyngeal bones and teeth essentially as in Catos- 

 tomvs. Isthmus quite l)road. Body generally elongate, subterete, and 

 little compressed. Scales quite small, 80-105 in the course of the lat- 

 eral line and 30-35 in a cross-series between dorsal and ventrals, usually 

 more or less reduced in size and crowded forward, as in Catostomus. 



