The Colors of Fishes 



231 



minnows of many species the male in spring has the skin charged 

 with bright pigment, red, black, or bright silvery, for the most 

 part, the black most often on the head, the red on the head 

 and body, and the silvery on the tips of the fins. At the same 

 time other markings are intensified, and in many species the 

 head and sometimes the body and fins are covered with warty 

 excrescences. These shades are most distinct on the most vigor- 



FiG. 170. — Blue-breasted Darter, Etheostoma cnmurum (Cope), the most brilliantly 

 colored of American river-fishes. Cumberland Gap, Tennessee. 



ous males, and disappear with the warty excrescences after the 

 fertilization of the eggs. 



Nuptial colors do not often appear among marine fishes, and 

 in but few families are the sexes distinguishable by dift'erences 

 in coloration. 



Recognition-marks. — Under the head of "recognition-marks" 

 may be grouped a great variety of special markings, which may 

 be conceived to aid the representatives of a given species to 

 recognize each other. That they actually serve this purpose is 

 a matter of theory, but the theory is plausible, and these mark- 

 ings have much in common with the white tail feathers, scarlet 

 crests, colored wing patches, and other markings regarded as 

 recognition- marks among birds. 



Among these are ocelli, black- or blue-ringed with white or 

 yellow, on various parts of the body ; black spots on the dorsal 

 fin; black spots below or behind the eye; black, red, blue, or 

 yellow spots variously placed ; cross-bars of red or black or green, 

 with or without pale edges; a blood-red fin or a fin of shining 

 blue among pale ones; a white edge to the tail; a yellow, blue, 

 or red streamer to the dorsal fin, a black tip to the pectoral 



