liEPORT ON ICHTHYOLOGY. 415 



had erroneously represented the species, or that the drawing had been wrongfully 

 interpreted by Rafinesque. It is also stated that there is no lateral line. This state- 

 ment is as certainly false as the other. The remainder of the description applies better 

 to the Pimelodus or Eoploddus limosus than to any other Siluroid of the Ohio. 



The generic diagnosis of Rafinesque describes the "Body scaleless, conical flat- 

 tened forwards and compressed beliind. Head very broad and flat with barbs, eyes 

 above the head. Two dorsal fins, l)oth with soft rays. Vent po.sterior." 



The numbers of the rays of the fins are not given; but the description of the fox'm 

 of the body and head, the position of the vent, the color, and we may even add the 

 popular name attributed to it, leave no room for doubt as to at least the generic iden- 

 tity of the Pijlodicfis limosMS Avith the HopJadelus limosus 



Another section, and the last one to be mentioned, into whicli Rafinesque tlivided 

 the Ictalnri, was placed as the third, and named Ameiurus. His generic characters 

 are the following: 



' ' Tail entire. Eyes round. Eight abdominal rays. Vent posterior. Dorsal fin 

 anterior with a sjiine. Lower jaw not longer. Pectoral fins with one simple spine and 

 seven rays." 



This section corresponds to the restricted genus of which the common Pimelodus 

 catits and Pimelodus Bekayi are the well-known representatives. Rafinesque refers 

 to the section four species which appear to be truly congeneric. Dr. Kirtland, in his 

 "Descriptions of the Fishes of Lake Erie, the Ohio River, and their tributaries,'' refers 

 to only one of these — the Pimelodus cuprcus. If we can rely upon the description of 

 Rafinesque, the Pimelodus lividus was not known to Dr. Kirtland. It may, however, 

 be the species described by that naturalist as Pimelodus cat us. There is little doubt 

 that the same is the case with the Pimelodus melns. The Pimelodus xanfhrocepJialus, on 

 the other hand, appears to be only a variety of the Pimelodus cupreus of the same 

 author. 



In identifying the sj^ecies of Rafinesque, we must, however, bear in mind that his 

 descriptions are generally so inaccurate or vague that of many of them we can never 

 be certain, and we can only have an approximate idea when the zoology of those places 

 which were so unfortunate as to i-eceive his attention has been exhausted. That un- 

 happy man had, nevertheless, a keen appreciation of natural aftinities; and had he been 

 less aben-ant, he would have ranked far ahead of most of the naturalists of liis day. 



As to the application of the name Pimelodus, it would apjiear necessary to reserve 

 it for one of those species refeiTcd to it by Lacdpede which has not been placed in 

 other genera or groups, arid which has been retained in the genus by its last monog- 

 rapher. 



the name of Beteiohraiichus sextcntacuIatuJi. It h.is a long second dorsal, which appears to be furnished with true rays. 

 On this character, Mr. Swainson has founded his genus P/croiio^w, and, totally deceived as toils allinities, has pl.aced 

 it between the genera PhractocephaJun of Agassiz and Sornhium of Spix in his subfamily of Soruhinw ; that group is 

 separated by the subfamilies .Upredina- (composed of true Anprrdinida' and of Eremopliili), and the SilHrinw from the 

 subfamily PimclodiiKr ; both of the latter groups are also composed of genera arranged in a fantastical and unnatural 

 manner. All of the characters of the Bcterobranchua sexteniaculaiiis indicate its aOiuity with the Pimdodina, and it is 

 indeed a true Pimelodus of Cnvicr and Valenciennes, and, according to the latter, is identical with his Pimelodim Sebw, and 

 consequently belougs to the genus Uhamdin of Bleeker, or Pimelonotus of Gill. The last two uames were published nearly 

 simultaneously, but Bleeker's has probably the priority. Swainsou's name could not be accepted, even if correctly 

 applied, as it has been previously given to a valid genus of Chiroptera. 



