Living Fishes 125 



Sculpins, the Percidae or Perches and Darters, and the Centrar- 

 chidae or Sunfishes and Bass. The Cottidae are easily recognized 

 by the absence of scales, squared caudal fin with rounded corners, 

 obtuse head, and two rounded dorsal fins, the second very long. 

 These characters are found in our Rocky Mountain Bullhead 

 (Cottus punctulatus of Gill), a species of our mountain streams. 

 It is a variable fish, and Cope has distinguished two other forms, 

 probably not distinct species. The Bullhead is considered harm- 

 ful, because it eats trout eggs and young trout. 



In the Percidae there are distinctly two dorsal fins, the 

 first spinous, the second soft. The large Wall-eyed Pike (Stizo- 

 stedion vitreum) has been introduced into some of our lakes, as 

 also has the Yellow Perch (Perca flavescens). Our native Perci- 

 dae are the various kinds of darters, comparatively or quite small 

 fishes, with the back little or not elevated. They live only in 

 the streams and rivers of the eastern foothills and plains regions. 

 Jordan now places them in a distinct family Etheostomidae, re- 

 marking that "these dwarf or rather concentrated perches are 

 peculiar to the waters of the eastern United States." The Johnny 

 Darter (Boleosoma nigrum mesaeum of Cope) is found at Boulder, 

 Longmont and Greeley. Technically, the genus is distinguished 

 by the possession of only one spine to anal fin; but the fish is 

 characterized by the black marks forming a sort of checker board 

 pattern, and spotted dorsal fins. The genus with two anal spines 

 is usually called Etheostotna, but it now appears that Poecilichthys 

 of Agassiz is its correct generic name. We have one species (P. 

 cragini of Gilbert) in the Arkansas basin, and one (P. exilis of 

 Girard)* in the South Platte drainage. Another species (P. 

 lepidus of Baird and Girard) is found near Roswell in New Mexico. 

 These records of darters are of peculiar interest, as they show the 

 western-most extension of this very characteristic North American 

 group. 



The only remaining family, the Centrarchidae,** resembles 

 the perches, but the spinous and soft dorsal fins are always more 

 or less united. The scales also differ from those of the Percidae. 

 A scale of a centrarchid type (Centrarchites color adensis) has been 



*Ellis and others call this P. iowae, but Dr. Hubbs writes that it should be P. exilis. 

 **The names have been revised by Dr. C. L. Hubbs, who has recently paid special atten- 

 tion to this family. 



