CHUB SUCKER. 823 
above, paler below, everywhere with a coppery or brassy, never silvery, lustre ; the fins 
are dusky or smoky brown, rarely reddish-tinged ; sexual differences strong; the males 
in spring with usually three large tubercles on each side of the snout, and with the anal 
fin more or less swollen and emarginate; adalt specimens with the back gibbous and 
the body strongly compressed, in appearance quite unlike the young; maximum length 
about 10 inches. 
Habitat, all waters of the United States east of the Rocky Mountains. 
Diagnosis —This is the only Sucker in Ohio without a lateral line which 
has not a series of black spots along the rows of scales on the sides of the 
body. | 
Habits—This species, like the two preceding, abounds in every brook 
and pond in the State of Ohio. It is one of the very smallest of the Suck- 
ers, rarely reaching the length of afoot. It is more than usually tenac- 
ious of life, and bites readily at a small hook, but is of very little value 
as food. The young are rather handsome fishes, the black lateral band 
being sometimes very distinct. In the aquarium they feed upou alge 
and the offal of other fishes. In the stomachs of specimens examined 
by Prof. Forbes, only confervee, diatoms, and mud were found. 
GENUS 21. MINYTREMA. Jordan. 
Minytrema, JORDAN, Man. Vert., 2d ed.. 1878, 318. 
Catostomus, Ptychostomus, Moxostoma, and Erimyzon sp., AUTHORS. 
Type, Catostomus melanops, Rafinesque. 
Etymology, minus, reduced ; trema, aperture, in allusion to the imperfections of the 
lateral line. 
Species with the form, squamation, and general appearance of Myxostoma, but with 
the air bladder in two parts, as in Erimyzon, and the lateral line imperfect, in the very~ 
young entirely obsolete, in half-grown specimens showing as 2 succession of deepened 
furrows, in the adult with perfect tubes, but interrupted, these tubes being wanting on 
some of the scales, especially posteriorly ; head moderate, rather broad above; mouth 
moderate, inferior, horizontal, the upper lip well developed, freely protractile, rather 
small, infolded, A-shaped in outline, plicated, with 12 to 20 plicz on each side; lower 
jaw without cartilaginous Sheath; eye moderate, rather high up, placed about midway 
of the head. Suborbital bones considerably developed, not very much narrower than 
the fleshy portion of the cheek below them, the posterior suborbital concavo-convex, 
about twice as long as deep, sometimes divided, the anterior somewhat deeper than 
long, often divided into two, sometimes united with the preorbita!, which is well 
developed and much longer than broad. The number and form of these bones, except 
as to their depth, are not constant in the same species, and do not afford specific char- 
acters; opercular bones well developed, not much rugose; fontanelle evident, rather 
large; gill rakers rather long, in length about half the diameter of the eye; isthmus 
moderate; phiyng al bones cssentially as in Myxostoma ; body rather elongate, sub- 
terete, becoming deep and rather compressed with age; scales rather large, nearly 
equal over the budy, the radiating furrows not specially marked ; lateral line as above 
