CATFISH GENUS NOTURUS RAFINESQUE 215 



caudal peduncle is stepped 3.3 times in the predorsal length; the 

 pectoral spines are stepped an average of 0.75 times in the peduncle 

 depth or 3.75 times in the distance from the dorsal origin to the adipose 

 notch. The specimen gives an impression of having been partially 

 dried, as do other Noturus {miurus and nocturnus) with which it was 

 collected. 



Body color light brown; anal fin with a dark brown submarginal 

 band; otherwise anal, pelvic, and pectoral fins with little pigment 

 except near bases; caudal fin light yellowish brown, with a yellowish 

 brown edge and a broad submarginal dark brown or black band; 

 adipose fin with a yellowish, translucent margin and an irregular 

 blotch extending about half way into fin; dorsal fin with a dark bro^vn 

 or black band through ends of rays, its base heavily pigmented, but 

 midsection relatively poorly pigmented; membrane of dorsal spine 

 (at least basal section) pigmented; lips and lower barbels yellowish, 

 poorly pigmented; lower lip with a suggestion of washed out pigment, 

 but bridge of pigment before pelvic fins a little heavier; otherwise 

 lower surface without pigment; head dark brown above and along 

 side, with large brown chromatophores on cheek and side; remnants 

 of dorsal blotches present but not obvious; one about anterior base of 

 dorsal fin, another between dorsal and adipose fins, and a third about 

 base of adipose fin but not extending to margin of that fin; the dark 

 brown or blackish band on caudal fin continues downward through the 

 upper procurrent caudal rays and up through the Tower procurrent 

 caudal rays to caudal peduncle where it diffuses or becomes indistinct. 



Discussion. — As judged from the several collections examined, 

 N. exilis appears to be rare at the locality of capture of the hybrid; 

 one specimen was taken but not recorded by Jordan and Gilbert; 

 Cross and Moore (1952) did not list exilis from Stations 28 or M3 

 (the hybrid locality), but an earlier collection (Station Miz) contained 

 the species. Elsewhere, in the Poteau River, N. exilis appears to be 

 more common; Cross and Moore recorded it from 13 collections as 

 Schilheodes insignis (Richardson). A^^. nocturnus and A^. miurus are 

 common at this locality and throughout the Poteau River. Both were 

 taken in the collection with the hybrid (Station M3) , although miurus 

 was not so indicated by Cross and Moore (1952, p. 407). 



The hybrid unquestionably involves Noturus miurus as one parent; 

 the recurved posterior serrae, the slight indication of anterior serrae, 

 the suggestion of brown saddles on the dorsal surface and the bands 

 of pigmentation on the procurrent caudal rays all indicate the subgenus 

 Rabida. Of this group, only A^. miurus is found in the stream. The other 

 species of Rabida in the drainage (A^. placidus) has neither a long 

 pointed caudal fin with a broad subterminal blackish band, nor the 

 pigmentation of the lower procurrent caudal rays. The low adipose 



