]S70.] 485 [Cope. 



.AMIURUS, Raf., Gill. 



This genus is by fai- the most nimisrously represented by species 

 among the Siluroicls of the United States. Twenty-five are known to the 

 writei", 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 Amsrica they are a most noticsable 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 Ictalur'..is 

 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 few, 17-22. 

 a Body slender, depth 1-8 length. 

 Anal radii 17: eye rather large. A. rLATYCEniALiTs. 



aa Body stouter; depth 1-5 or legs length. 

 l3 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. ^kltjrus. 



/?/? Upper jaw equal or exceeding lower. 



* Anal radii 17. a. put,lus. 



** Anal radii 19-22. 

 f Ventral radii 8, 

 Head width 4.5 to 4.63 times in length; diameter eye 4.5 times between 

 orbits; depth 3.75 in Isiigth, beards rather short, humsral process smooth. 



a. NEBUL0SC9. 



Width head four tim33 in length, depth 3.63 times; eyes 4.5 between 

 orbits; colors light; beards as above. a. cattjlus. 



Width head 4 times in length; eye 4; otlier characters as above; colors 

 dark. a. catulus, yar.- 



ff Ventral radii 7. 



Eye larger, 3.75 times into iuterorbitil width; head narrowed, width 

 4.66 times in length; black. a. mispilliensis. 



A A The anal fin longer, the radii 24-8. 



To this group belong 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. 



* I refer a spacimsn whici I took at Poug'ikeepsle on tUj Hul'son River, to tliiS-S;j9cies, 



A. P. s. — TOL. xr. — 33e 



