NATURAL HISTORY OF AMIA CALVA LINNAEUS. 93 



(2) The portions of the dorsal, anal, and caudal proximal to the black bands 

 have changed from orange to bright lemon, while the portions of these fins between 

 the bands remain a brilliant orange. 



(3) On the lower part of the opercle in front of the vertical orange band are three 

 horizontal yellow stripes converging caudally. The larva has now reached its 

 maximum of brilliancy. 



Larvae of 100 [millimetres. Larvae of this size do not differ essentially in 

 color from those of 70 millimetres. The black bands on the fins are more 

 pronounced and perhaps broader. The chief difference is that the dark reticula- 

 tions on the sides are now faintly marked. There are as yet no sexual differ- 

 ences in color, though the sexual organs are differentiated. (Compare Wilder's 

 brief foot-note, 76, p. 165, describing larvae 75 to 100 millimetres long, and 

 Dean, '96 a .) 



Larvae of 170 millimetres. Fish of this size I have not seen living, but through 

 the kindness of Professor Nachtrieb I have some formalin specimens. The dark 

 reticulations on the sides are very distinct and about 3 millimetres wide. The 

 enclosed spaces are irregular, in about three longitudinal rows, and the spaces are 

 about as wide as the reticulations. The dorsal still has the black band and black 

 border, the anal has one band, and outside this reticular markings like those on the 

 body. The anals and paired fins and the body of the caudal and anal are trans- 

 parent white. The head-stripes are still very prominent. The specimens show no 

 sexual color differences. 



Larvae of 25 centimetres. In order to complete the cycle of color changes a 

 note may be added on several fish 25 centimetres long and probably one year old, 

 speared April 12. The fish have now assumed the adult colors, and the sexes are 

 distinguishable by color. The male is in breeding dress. The orange tinge on the 

 sides is more pronounced than is usual in older fish, and becomes a pure orange at 

 the base of the tail. The reticular markings on the sides are nearly black bands 3 

 millimetres wide and enclosing areas about 1 centimetre in diameter, and irregularly 

 diamond-shaped. There are about four longitudinal rows of such areas. The tail 

 has three parallel V-shaped bands with caudally directed apices. The tail-spot is 

 well marked and orange-bordered. The female (30 centimetres long) is like the 

 adult female. The reticulations and the V-shaped bands on the tail are scarcely 

 distinguishable. The above descriptions, except that of the 170-millimetre fish, 

 apply only to fish newly taken from the natural waters. Those reared in confine- 

 ment grow less rapidly and develop larval colors while smaller. Their colors are 

 also less brilliant. 



