lO 



BULLETIN OP THE BUREAU OF FISHERIES. 



Fig. l6.—Bairdiclla chrysura. Newly hatched fish, actual length i.S mm. 



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The oil globule appears as a yellowish opaque body on the surface of which are scattered 

 a few yellow chroniatophores. It is located in the posterior region of the yolk sac. The 

 fin folds are continuous. The dorsal fold arises just posterior to the head; the ventral 

 fold is continuous with the yolk sac. The depth of each fin fold is less than the depth of 



the body. The body is 

 brownish yellow, marked by 

 five vertical yellow bands. 

 These vertical bands are 

 composed of more or less 

 closely aggregated chromato- 

 phores. A few scattered 

 chromatophores occur also 

 between the vertical bands. 

 The fin folds and the posterior tip of the body are transparent. Figure i6 illustrates a 

 larval fish about two hours after hatching. 



For some time after hatching the general color of the body remains unchanged. 

 The distribution of the yellow chromatophores, however, undergoes marked changes. 

 Five hours after hatching (fig. 17) the vertical bands have become broken up. A. 



distinct vertical yellow _ 



band remains located ap- 

 proximately two -thirds / ^— i .'^ :'^^^.-.':-:-A'^f2'yif*y! 

 the distance from the 

 vent to the posterior end 

 of the body. Another 

 less distinct vertical band 

 occurs just posterior to 

 the head. Groups of 

 scattered chromatophores occur in the head region and above the vent. A few more 

 or less isolated chromatophores occur also on the posterior half of the body. 



At one day after hatching (fig. 18) the young fish has grown to a length of 2.4 

 to 2.6 mm. A small mass of yolk remains unabsorbed. The head is no longer de- 

 flected, but slightly elevated. The body is distinctly flattened. The greatest depth of the 



^ body occurs posterior to 



"t^:::.'''" "• ^_ the head. From this 



/V>ia . .•. <3 ■ ,iI''/Vy>^'':*?«5~ ''"•-. point the body tapers 



gradually toward the 

 posterior end. The 

 depth of each fin fold is 

 greater than the depth 

 of the posterior half of 

 the body. The general color of the body remains brownish yellow. The fin folds and the 

 posterior one-fifth of the body remain transparent. The yellow chromatophores have 

 become fewer. The posterior vertical band now consists of a dorsal and a ventral group 

 of chromatophores. There is no distinct vertical band in the anterior region at this 

 stage, but a few yellow chromatophores remain scattered over the head and the anterior 

 region of the trunk. 



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Fig. 17, — Bairdiella ckrysura. Larval fish^ to 5 hours after hatching, actual length a nun. 



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Fig. iS. — Bairdiella ckrysura. Lar\'al fish i day after batching, actual length 2.5 mm. 



