64 NATURAL HISTORY OF AMIA OALVA LINNAEUS. 



June 26. Temperature of dark aquarium 27.5 C, of light aquarium 22.5 C. 

 Both fish colored as before and no noticeable difference between them. 



Thus neither light nor temperature appears to affect the intensity of the colors. 

 The color change is probably referable to internal causes. The physical cause of 

 the color has not been investigated. 



2. Habits Not Peculiar to the Breeding Season. Little is known of Amia at 

 other than the breeding season. Cuvier ('31) refers to it as feeding on crayfish. 

 Kirtland ('41) found crayfish in the stomach of one individual. Cuvier and Valen- 

 ciennes ('46) found fish and aquatic insects in the stomach of those dissected. 

 Fiilleborn ('94) adds small fish to the diet, while Dean ('98) confirms earlier obser- 

 vations on the food, and adds: "A female measuring twenty-eight inches . . . had 

 eaten, among other things, a pickerel twelve inches in length. Another, a female 

 measuring thirty-one inches, contained the (vertebral) columns of eleven fishes each 

 . . . about three inches in length. Another, taken at twilight near the margin 

 of a rubbish heap, had eaten scraps of meat and a lump of a raw potato. ... I 

 have found no evidence that the dogfish eats fish, or more accurately some fishes, after 

 they are dead. Dead perch and sunfish remain untouched, even in regions where 

 Amia is very abundant." The name "Mudfish," under which Garden's specimen 

 was sent to Linnaeus, indicates its habitat, as does that of "Marshfish" given it by 

 Richardson ('36). Kirtland ('38) says of it: "The dogfish is found in Lake Erie, 

 where it is frequently called 'The Lake Lawyer.' It is distinguished by its fero- 

 cious looks and voracious habits (unde nomen?). The flesh is rank, tough, and 

 not eatable. To the anglers it is a troublesome nuisance, by taking their bait and 

 often breaking their hooks and lines, which it can readily do by means of its large 

 teeth and long jaws." Suckley ('60, p. 365) says: "They readily bite at a hook 

 covered with ordinary bait, and when hooked endeavor to escape by feats of strength 

 and skill equal to those of fish of much higher repute. The flesh is soft and pulpy 

 and is popularly believed to be poisonous.'' Hallock ('83) adds: "They have been 

 known to bite a two-pound fish clean in two, the very first snap. They are as 

 tenacious of life as the eel." Fiilleborn ('94) notes that they emit a low sound when 

 out of the water, either voluntarily or when the abdomen is compressed. Dean ('96, 

 p. 415) finds that "it feeds mainly during the evening and at night, but even then 

 he [the fisherman] meets it occasionally when using the jacklight." Whitman and 

 Eycleshymer ('97) report that "Amia is very shy and nocturnal in its habits." 

 Dean ('98) later modified his opinion thus: "At night, . . . judging from my own 

 experience with set lines, the fish is not often taken. And the result of my later 

 observations is not favorable to the view that the dogfish is distinctly nocturnal in 



