30. CATOSTOMID^E PANTOSTEUS. 121 



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

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

 more than half the length of the base of the fin, the rays 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 about 

 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 peculiarities 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, (-/.bzhoq, round; As-ro?, slender. "The name means 

 small round mouth." Rafmesquc.) 



122. C. eSosig'atiHS (Le Sueur) Ag. Blade Horse; Gourd-seed Sucker; Missouri 

 Suclcer; Suckerel. 



Depth 4-5 in length ; head 6-S-|. Eye small, 6-7 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 9-56-7. 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 eloiif/atiis Le Sueur, Jourii. Acad. Nat. Sci. Pkila. 1817, 103: Sclcrogna- 

 thus elonr/alus Giiiitlier, vii, 23; Jordan, 1. c. 189.) 



63. PANTTEU Cope. 

 Hard-headed Suckers. 



(Cope, Lieut. Wheeler's Expl. AV. 100th Mer. v, 673, 1876 : type Minomus platyrhynchus 

 Cope.) 



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

 and rather broad above, anteriorly somewhat pointed. Eye rather 

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

 as in Catostomus. Bones of head rather thick, the two parietal 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 Chondrostoma, Acrocliilus, 

 and related genera. Upper lip broad, papillose, with a rather broad, 

 free margin and 2 or more series of tubercles. Lower lip 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- 

 tomus. Isthmus quite broad. 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. 



