30. CATOSTOMIDJi: MOXOSTOMA. 
137 
slieatb. Muciferons s;>’«teui considerably developed, a chain of tubes 
along the supraorbital region, a branch of which extends around 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. Gill-raliers weak, moderately long. Pharyn- 
geal bones rather weak, much as in Erimyzon and Catostomus, the teeth 
rather coarser, strongly compressed, 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, usuall}' about II in the lateral line (Il-oG) 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 bodj', its tirst rays usually rather nearer snout than the cau- 
dal, the number of dev^eloped rays usually about 13, but vaiying in dif- 
ferent species from 11 to 17. Anal tin short and high, usually emargi- 
nate in the male fish, probably" always with 7 develoiied rays. Yentrals 
inserted nearly under the middle of the dorsal ; their number of raj’s 
normally 9, occasionally varying to 10; the occurrence of 10 ventral rays 
is pi^bably an accidental individual character, and not a permanent spe- 
cific one. Caudal fin deeply forked, the lobes about equal, except in two 
species. Air-bladder with three chambers. Skeleton essentially as in 
Catostomiis, the vertebrm in ill. carpio 27-11. 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 difficult to distinguish, and have perhaps 
been unduly multiplied by authors, to suck; (rrona^ mouth; 
hence, more properly Myxostoma.) 
* Lips full, strougly x^apillose. 
152. I7I. l>S5pall3o§cassi (Cope) Jordan. 
Body comparativ^ely stout, the dorsal region somewhat elevated and 
lounded, the depth being’ about I in length, the head about the same. 
Eye rather large, high up and well back, the preorbital space being 
longer than the other species. Top of head flat. Dorsal rays 12-11. 
Scales rather large, G-I2-5. Lii)S well developed, deeply incised. 
