or 
1870.] 485 (ope, 
AMIURUS, Raf. Gill. 
This genus is by far the most numerously represented by species 
among the Siluroids of the United States. Twenty-five are known to the 
writer, and several others have been described which are not satisfactorily 
distinguished. Besides the United States, China is included in the range 
of the genus. In North America they are a most noticeable feature of the 
ichthyological fauna of the Eastern Coast Streams, abounding there in 
individuals and species, far more than in the tributaries of the Mississippi, 
where Ictalurus is the prevailing form. The tributaries of the Great 
Lakes furnish another resort for them, and the rivers of Texas, according 
to Girard, also abound in them. This distribution in relation to Ictalurus 
is to be found in the fact that they are lovers of mud and sluggish waters, 
while the latter genus prefers running streams and rivers. 
The species of Amiurus fall into four sections as follows : 
I. Caudal fin rounded or truncate when spread open. 
A The anal radii tew, 17-22. 
aBody slender, depth 1-8 length. 
Anal radii 17; eye rather large. A. PLATYCEPHALUS. 
aa. Body stouter ; depth 1-5 or less length. 
8 Lower jaw longer than upper. 
. Anal radii 20, its basis 5.5-6. times in length; head narrowed anteriorly, 
body not shortened. A. DEKAYI. 
A. 22, head broad, body short. A. ASLURUS. 
£8 Upper jaw equal or exceeding lower. 
* Anal radii 17. A. PULLUS. 
** Anal radii 19-22. 
+ Ventral radii 8. 
Head width 4.5 to 4.66 times in length; diameter eye 4.5 times between 
orbits ; depth 3.75 in length, beards rather short, humeral process smooth. 
A. NEBULOSUS. 
Width head four times in length, depth 3.66 times; eyes 4.5 between 
orbits ; colors light ; beards as above. A. CATULUS. 
- Width head 4 times in length ; eye 4; other characters as above ; colors 
dark. A. CATULUS, var.* 
{t+ Ventral radii 7. 
Eye larger, 3.75 times into interorbital width; head narrowed, width 
4.66 times in length ; black. A. MISPILLIENSIS. 
AA The anal fin longer, the radii 24-8. 
To this group belongs A. cupreus, Raf., A. cupreoides, Gird., A. atra- 
rius, DeK., A. catus, Linn, A. nigricans, Les., A. coenosus, Rich’n, A. 
felinus and A. antoniensis of Girard. 
II. Caudal fin furcate or strongly emarginate. 
A Anal fin with few radii, (19-22). 
a Caudal fin merely emarginate. 
*L refer a specimen which I took at Poughkeepsie on the Hudson River, t» this species- 
A. P. 8.—VOL. XI.—23E 
