ase 
ES —— = 
eee 
. 
—~ 
L, Agassiz on the Ichthyological Fauna of Western America. 75 
inner margin into a prominent point. Fig. 
1, a, represents the inner surface of the 
right pharyngeal, 6, the dental edge of the 
two pharyngeals in their natural position, 
eand d, magnified teeth in profile. 
The anterior lobe of the long dorsal is 
slender, its third and fourth rays being 
prolonged beyond the following ones itito 
ong filaments. The lower fins are all 
pointed, rather small, and hence distant 
from one another. The ventral ridge of 
the body is flat. ‘The scales have many 
narrow, radiating furrows upon the anterior field, and one, more 
deeply marked, ina straight line, across the lateral fields, or limit- 
ing the lateral and posterior fields, hardly any upon the anterior 
field, the waving of the broader concentric ridges producing only 
a radiated appearance upon that field. Tube of the lateral line 
straight and simple, arising in advance of the centre of radiation, 
which is seated in the centre of form of the scales. 
Cuvier referred erroneously the type of this genus to his ge- 
nus Labeo, in which he has been followed by DeKay, whilst — 
Valenciennes founded upon it his genus Sclerognathus. Rafin- 
having the priority, must therefore be retained. Moreover Valen- 
Clennes describes as a second species of that genus under the 
hame of Sclerognathus Cyprinella, a fish from Lake Pontchar- 
train, which belongs to Rafinesque’s genus Ichthyobus, as | shall 
now below. In recognising the generic differences which dis- 
tinguish these two fishes, Rafinesque has really been much in 
advance of more recent observers, though the characteristics he 
ascribes to them are very loosely and imperfectly drawn. ie 
I know now four species, of this curious genus, oue of which in- 
habits the fresh waters of our middle States, emptying into the At- 
lantic, the Catostomus Cyprinus of Lesueur; another occurs in 
Lake Champlain and the waters of our Northern States, emptying 
into the St. Lawrence, the Catostomus Cyprinus of the Rev. Zad. 
‘fompson ; a third is found in the Ohio, and its tribntaries, and 
has heen described under the same name as the preceding ones, b 
Dr. Kirtland in his “ Fishes of the Ohio.” [have lately obtained a 
fourth from the Osage River; through the kindness of Mr. George 
Stolley, which I have inscribed as Carpiodes Bison in my notice 
of the Fishes of the Tennessee River.* It occurs also in the 
Mississippi, above its junction with the Missouri, as I have ascer- 
tained recently from specimens forwarded to me by Dr. Rauch of 
Burlington, lowa; whether it is found farther south, 1 do not 
MOW i 5 
* See this Journal, 2nd Ser., vol. xvii, p. 356. 
