50 Kendall — Notes on Percopsis guttatus and. Salmo omiscomaycus. 



idae and the majority of the characters are of that order. But- 

 later another fish of the family was discovered by Eigenmann, in 

 the Umatilla River, Oregon, still more decidedly percoid in its 

 structure, justifying the provisional disposition of the family in 

 the Acanthopteri by Jordan and Evermann. 



This fish was described by Eigenmann and Eigenmann as a 

 new genus and new species under the name of Columbia trans- 

 montana, in Science, Oct. 21, 1892, p. 233. 



In apparent recognition of the generic name bestowed upon 

 the fish by Thompson, Jordan and Evermann have established 

 the suborder Salmopercae for these fishes, of which they have the 

 following to say: 



We place provisionally as a suborder of the Acanthopteri, a 

 singular group of archaic fishes, relics of some earlier fauna, 

 and apparently derived directly from the extinct transitional 

 forms through which Haplomi and Acanthopteri have descended 

 from allies of the Isospondyli. The group shows the remarkable 

 combination of true fin spines, ctenoid scales, and a percoid 

 mouth, with the adipose fin, abdominal ventrals, and naked 

 head of the Isospondyli. The relations of the Percopsidse with 

 such archaic spiny rayed fishes as Aphredoderus and Elassoma 

 are certainly not remote and the close resemblance of the head 

 of Percopsis to that of Gymnocephaliis (Acerina) may be more 

 than accidental." 



Accordingly the classification of this little group is as fol- 

 lows: 



Order. Acanthopteri. 



Suborder. Salmopercae. 



Family. Pereopsidae. 



,-, f Percopsis, omiscomaycus. 



(jrenera. i r , -, , • ' 



[ Columbia, transmontana. 



Key to the Genera. [After Jordan and Evermann.] 

 a. Dorsal fin with 2 feeble, slender spines or simple rays; 

 anal with 1 slender spine ; scales most strongly ctenoid on cau- 

 dal peduncle; posterior margin of preopercle entire or with 

 feeble crenulations; lateral line developed, the tubes small; 

 form slender; the body translucent. Percopsis. 



aa. Dorsal and anal each with two very strong spines; ven- 

 tral spine evident; scales most strongly ctenoid on anterior part 

 of body ; posterior margin of preopercle with a few short but 



