THE GERMAN CARP IN THE UNITED STATES. 531 



darker in its posterior half; the rays themselves are of about the same 

 color. The anal is yellowish-red, while the pectoral and pelvic fins 

 are grayish or yellovrish, tending* to red toward their tips. The upper 

 lobe of the caudal fin is of about the same color as the dorsal; the 

 lower lobe has a lighter, yellowish cast, with more or less red. especially 

 toward the end. 



The coloration is influenced b}- the age of the fish, the character of 

 the water in which it lives, its nutrition, the season of the year, its 

 sexual condition, and by the other conditions of its environment. 

 Seeley (1*80, p. 97) states that unsymmetrical coloring - is sometimes 

 found and that a fish may have glittering golden stripes on one side of 

 the ]>od\ and pale steel blue on the other. Sometimes typical carp are 

 black, bluish, green, red, golden, silvery, or even white, and Doctor 

 Fatio records that he has kept in confinement carp which were origi- 

 nally green or golden, but which became colorless in an opaque vase. 

 It is not an unusual thing to see in carp that have died out of water 

 a reddish suffusion, especially marked in the fins, probably due to the 

 congestion of blood in the capillaries as the circulation is stopped. 



In common with the other members of the family, the mouth of the 

 carp is without teeth, the only organs of this description being the 

 blunt, knob-like structures lying on the pharyngeal bones in the back 

 part of the mouth, or "throat.* 1 These are entirely for grinding 

 food, and, as is obvious both from their position and shape, are of no 

 use in grasping, this function 1 icing performed by the so called lips. 

 The alimentary tract is comparativel}' long, but uncomplicated; the 

 stomach is a simple tube not sharply differentiated from the esophagus 

 and without a blind sac, while the intestine has no pyloric appendag 

 The entire alimentarv tract from the beginning 1 of the stomach" is 

 usually two to two and one-half times as long as the body. The air 

 bladder is large, with tough, thick walls. A transverse constriction 

 divides it into two parts; the posterior of these is the smaller and 

 ends in a rounded point, while the anterior portion is larger and has 

 its base somewhat bilobed. 



RACES AND VARIETIES. 



The great range and frequency of variation in the carp is undoubt- 

 edly largely due to its domestication or semidomestication since early 

 times. As is to be expected, this has resulted in the naming of a large 

 number of varieties or races. In Europe, where carp culture is car- 

 ried on systematically, these races are kept pure and true, so far as 

 possible; but in this country no attention has been paid to them, at 

 least in recent years, so that we need not treat them in detail here. 

 Those interested in the subject will find an exhaustive account in the 

 contribution entitled "liber Karpfenrassen," by Dr. Emil Walter, in 



a The position of the thoracic septum is here taken as the beginning of the stomach. 



