CATFISH GENUS NOTURUS RAFINESQUE 67 



Minnesota, is still doubted. Another dubious record, the sole one in 

 the Missouri River drainage, Iowa, was recorded by Cleary (1956, 

 map 65) as Lake of Three Fires, Taylor County. Subsequent efforts 

 to re-examine the specimen have been fruitless, as the specimen 

 was presumably discarded in the field (personal communication from 

 Robert E. Cleary). 



Specimens of Noturus Jlavus and of Noturus nocturnus have been 

 identified as this species; Noturus insignis has been confused with it. 

 Table 9 is intended to facilitate the identification of young individuals 

 of exUis and similar species. 



Nomenclature. — As indicated under Noturus insignis, the action 

 of Hubbs and Raney (1944) in transferring the name Pimelodus 

 insigne Richardson to the identity of Noturus exUis is invalid. That 

 name belongs to the eastern species, here called Noturus insignis. As 

 shown in the above synonymy, the first available name for the present 

 species is Noturus exUis Nelson. 



The original description of Noturus exilis was supplemented by 

 Jordan (1877b, p. 372) who gave diagnostic characters from the types. 

 Some of these are: "Pectoral spines very strongly serrated behind . . . 

 with five or more prominent recurved hooks . . . , jaws nearly 

 equal . . . color nearly uniform; tip of dorsal blackish." In addi- 

 tion, his figure (1877d, pi. 38, fig. 59b) of one of the types confirms 

 the presence of a sub terminal lower jaw and the serrated pectoral 

 spine. There can remain little doubt about the application of the 

 name Notwus exilis. 



The holotype (USNM 29677) of Noturus elassochir from Napier- 

 ville, Illinois, which was described later by Swain and Kalb (1883), 

 also belongs to this species. It is a large individual, 117 mm. in total 

 length or 99.8 mm. in standard length, and the body form, sub- 

 terminal jaws, spines, and premaxillary tooth band are typical. On 

 each side there are: one internasal pore, ten preoperculomandibular 

 pores, nine soft pectoral rays, and ten pelvic rays. The anal fin has 

 19 rays, the caudal fin has 19+9-|-12-l-ll = 51 rays, and there are 

 38 vertebrae. 



Etymology. — The name exilis (Latin) means slender, referring to 

 the slim body. 



Relationship. — Noturus exilis has previously been confused \vith 

 and considered an intimate relative of Noturus insignis, chiefly on 

 the basis of a relatively long body and anal fin and a similarity in 

 color pattern. These characters are misleading, however, as important 

 differences between the two are to be found in the structure of the 

 pectoral spine, the form of the caudal fin and number of hypurals, 

 the shape of the skull, the difference in position of the mouth, and 

 in the structure of the sensory canal system of the head. Instead, it 



