18S7.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 47 



DESCRIPTIONS OP NEW AND LITTLE KNOWN ETHEOSTOMOIDS. 

 By CHA.<^. H. OILBERT. 



The present paper is occupied chietl}^ with the descriptiou of new 

 Etheostomoids collected during the summer of 1884, in the course of a 

 series of explorations of streams of the South and Southwest, under- 

 taken in the interests of the U. S. National Museum. The writer was 

 associated with Prof. Joseph Swain in field work in Indiana, Kentucky, 

 Tennessee, and Alabama ; with Prof. S. E. Meek in Southwestern 

 Missouri; and with Prof. D. S. Jordan in Arkansas and Texas. 



Types of all of the new species here characterized have been de- 

 posited in the National Museum, their numbers on the Museum register 

 being cited at the beginning of the descriptions. 



The species described come under the current genera TJlocentra^ 

 Cottogaster, Hadroptenis, Bhothceca, Etheostoma, and Alvarius. It is 

 not believed that these now admit of satisfactory generic characteriza- 

 tion, and they are here recognized as convenient subgeneric divisions 

 only. Characters based in this group on the protractility or nonpro- 

 tractility of the i^remaxillaries, the union or non-union of the branch- 

 iostegal membranes, and the completeness or incompleteness of the 

 lateral line, may indicate real affinity, but I think we are hardly pre- 

 pared to insist that they always and of necessity must do so. 



What are apparently geographical varieties have been described in 

 order to call attention to them. Their claim to subspecific rank can- 

 not be established until further exploration shall have determined the 

 limits of variation within the species. The entire question of the rec- 

 ognition of subspecies among the Etheostomoid s must for the present 

 be treated as an open one. 



1. Etheostoma (Ulocentra) histrio Jordan & Gilbert, sp. uov. 36386, 36409, 36448. 



In form much resembling Etheostoma zonale, but the body slenderer 

 and less compressed, and the anterior profile of head more declivous, 

 the mouth being on a level with lower portion of base of pectorals. 

 Mouth small, horizontal, subinferior, the lower jaw included ; maxillary 

 reaching vertical from front of pupil, 3^ in head. Eye rather large, 

 high up on sides of head, its diameter much greater than length of 

 snout, 3 in head. Interorbital width half vertical diameter of orbit. 

 Parietal region narrow, smooth, rather strongly' arched. Opercular 

 spine little developed. Gill-membranes broadly joined across tlie isth- 

 mus. Premaxillaries technically ijrotractile, the upper lip everywhere 

 separated by a fold from the skin of the forehead; they are, however, 

 very little movable. 



Vertical fins small, the paired fins greatly developed. Spinous and 

 soft dorsals separate, nearly equal in height and extent; the longest 



