lO  BULLETIN OF THE BUREAU OF FISHERIES. 



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

 a few yellow chromatophores. 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 



Via.-,6.-BairdielUchrymTa. Newly hatched fish, actual length i.S mm. chrOmatOphorCS OCCUT 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- /^'p^.Z.''''.^'^'-'i>t^.'~^, - ^ 



proximately two - thirds /^^ .- -^ ffi^fe^-..!.YV<^^ --, 



the distance from the V'^y ^^'^^^-SiliiaSS^ ) 



vent to the posterior end ^\^ './'^•%. / ..-- 



of the body. Another '\ 'K'"^.)^ ' 



less distinct vertical band *'"•— ~^i::~.---'*^'' 



J ^ Fig. 17. — Batrdiella chrysura. Larval fish 4 to s hours after hatching, actual length 2 mm. 



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. i8) 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^^'''" *'^— ^^ tljg head. From this 



/V^^ . (3 • ,i,^'///?7w?»5=~».^_ ~''-,, point the body tapers 



'-v^^gS^ 7P-i;^«-"i^'^ir.titrX-^^^ '; gradually toward the 



^~'~'^'>.^C^\y^^i^!i^ ...—'-''' posterior end. The 



"~~— ..^ depth of each fin fold is 



Fk. ii—Bttirdiella chrysura. Larval fish i day after hatching, actual length 25 mm. greater than the deptn 



of the posterior half of 

 the bod}'. 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. 



