30. CATOSTOMIDiE MOXOSTOMA. 137 



slieatli. Miiciferous system considerably developed, ii cliaiu of tubes 

 alou!^" the supraorbital regiou, a braucli of which extends arouud be- 

 hind the eye and forwards along the suborbital bones and the lower 

 edge of the preorbital. Opercular bones moderately developed, nearly 

 smooth. Isthmus broad. G ill-rakers weak, moderately long. Pharyn- 

 geal bones rather weak, much as in Enmyzon and Catostojnus, the teeth 

 rather coarser, strongly comx)ressed, the lower 5 or G much^stronger 

 than the others, which are rapidly diminished in size upwards, each 

 with a prominent internal cusp. Scales large, more or less quadrate in 

 form, nearly equal in size over the body, and not specially crowded- any- 

 where, usually about 44 in the lateral line (41-5G) and about 12 series 

 between dorsal and ventrals. Lateral line well developed, straight or 

 anteriorly curved. Fins well developed, the dorsal inserted about mid- 

 way of the body, its first rays usually rather nearer snout than the cau- 

 dal, the number of developed rays usually about 13, but varying in dif- 

 ferent species from 11 to 17. Anal fin short and high, usually emargi- 

 nate in the male fish, i)robabl3' always with 7 developed rays. Ventrals 

 Inserted nearly under the middle of the dorsal ; their number of rays 

 normally 9, occasionally varying to 10; the occurrence of 10 ventral rays 

 is i)robabl3" an accidental individual character, and not a jiermauent spe- 

 cific one. Caudal fin deeply forked, the lobes about equal, except in two 

 species. Air-bladder with three chambers. Skeleton essentially as in 

 Catosfomus, the vertebrie in ilf. carpio 27-14. Sexual peculiarities little 

 marked, the males in the spawning season with the lower fins reddened, 

 and the anal rays swollen and somewhat tuberculate. Species very nu- 

 merous in the United States east of the Eocky Mountains. They 

 spawn in spring, running up from the rivers into the smaller streams 

 for that purpose. They are difQcult to distinguish, and have perhaps 



been unduly multiplied by authors, (/-kj^w, to suck; o-rw/za, mouth; 



• -> 

 hence, more i)roperly Myxostoma.) 



'Lips full, strongly papillose. 



152. in. pa.paiaosum (Cope) Jordan. 



Body comparatively stout, the dorsal region somewhat elevated and 

 lounded, the depth being about 4 in length, the head about the same. 

 Eye rather large, high up and well back, the ])reorbital space being 

 longer than the other species. Top of head flat. Dorsal raj's 12-14. 

 Scales rather large, 0-42-5. Lips well developed, deeply incised. 



