86 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



posterior sides of the abdominal cavity. The fin fold remains entire. A reduction 

 in the length of the gut occurs at 2.5 mm. and what appears to be a secondary, or 

 true vent is developed anterior to the gut. Several young at this length showed this 

 peculiar structure, the exact nature of which has not been determined (fig. 3). 



Figure 2. — Peprilus ahpidotus. From a specimen 1.8 mm. long. 



The harvestfish at 3.5 mm. is more compressed, the gut has become greatly 

 reduced and only one vent is evident. The location of the chromatophores becomes 



Figure 3.— Peprilus ahpidotus. From a specimen 2.5 mm. long. 



more elevated. The fin rays are slightly differentiated, although the fin fold remains 

 entire (fig. 4). 



The young fish can be easily recognized at 7 mm. for the fin rays are fully differ- 

 entiated. A further deepening of the body takes place and the chromatophores 



•••,■•.*■••* /*. 



**»• 



Figure 4. — Peprilus alepidotus. From a specimen 3.5 mm. long. 



become more scattered, enlarged, and anastomosed. The pigmentation is confined 

 to the forward part of the body (fig. 5). 



The young fish becomes still further compressed at 9 mm. The pigmentation 

 is darker and a considerable reduction in the size of each chromatophore occurs 

 (fig. 6). 



The fish has assumed a characteristic adult shape at a length of 62 mm. The 

 body has become strongly compressed, deep, and oval. The caudal fin has become 

 forked, while the dorsal and anal fins are similar in shape and notably elevated ante- 



