330 Fishes of the Ohio 
here described, have been necessary and most potent agents 
in the dispersion of erratic blocks, particularly such as lie in 
long and narrow surface trains, we wish equally to advocate 
the efficiency of that other gigantic force of transport which 
water possesses when it moves in the manner of those enor- 
mous waves of translation, whose origin, functions and 
energy we have endeavored to exhibit to the reader. The 
boulders of New England give evidence of having been 
conveyed by both these agencies, the more angular and nar- 
row trains by the lifting power of vortices ; the more worn, im- 
bedded, and irregularly scattered blocks, by the propelling ac- 
tion of the general current and its mighty waves. 
Art. XXIV. — DESCRIPTIONS OF THE FISHES OF LAKE ERIE, THE 
OHIO RIVER, AND THEIR TRIBUTARIES. By Janep P. KIRTLAND, 
D 
(Concluded from page 276.) 
PrwELopvs. Cuv. 
P. catus. Lin. Bull-head. 
Cat- fish. | am rw ia vol. 
Silurus catus. Lin ak nal d 
EM Common Freshwater Cat-fish. Mitchill, Trans. Lit. an 
Phil. Soc. N. RE vol. i. 
P. die c à 
Pimelodus nebulosus. Lo Mémoires a 
Muséum ,vol. v. P- 149. 
T " H : Biens Refs p. l L 
Le Pimélode chat. Pimelodus catus. Cuv. et Val. xv. P- 12 
Le Pimélode nebuleux. Pimelodus nebulosus. TT E. s l. 
Pimelodus catus. Common Cat-fish. jns nep. p. 182, Pl 
XXXVII. fig. 119- 
Plate XXVL Fig. 1. 
Head flattened above and beneath, widest at its base, 
full 
the eyes. Jaws equal. Cirrhi eight, arranged, tw? 
