SHORT BIGEYE IN WESTERN NORTH ATLANTIC 



127 



Fir.DRE 14. — Pelagic prejuvtnile Pseudopriacanthus alius, 19.9 mm. standard length (WHOI). 



By 2.4 mm., a single series of closely arranged 

 chromatophoros ]wd developed along the ventral 

 midline of the postanal region, and very light pig- 

 mentation had appeared at the angle of the 

 preopercle. 



By 2.6 mm., pigmentation on the preopercle had 

 spread to cover the basal two-thirds of the spine 

 at the angle. In addition, pigment seemingly on 

 the dorsal surface of the gut liad intensified very 

 noticeably and had begun to spread down over 

 the sides of the gut. A 2.7-mm. individual also 

 had several chirk spots along the edge of the 

 isthiuus, the gill arches were darkening, a patcli 

 of snudl clu'oniatophores was (>vi(h'nt at the point 

 where the tubular and bulky parts of the gut join 

 within the dorsal region of the body cavity, and a 

 single large chromatophore was present at the anal 

 opening. In a second 2.7-mm. specimen the 

 patch of pigment at the junction of the two sec- 

 tions of the gut extended along the apparent 

 dorsoposterior surface of the tubular gut lu-arly 



to the anus. In both. of these 2.7-mm. specimens 

 there was a general darkening of the body, al- 

 though individual chromatophores were not evi- 

 dent. At 3.2 mm. (fig. 9), a few snuxU pigment 

 spots were present on the caudal finfold. The 

 chromatophores on the optic lobes or on the brain 

 case had descended laterally. 



The chromatophores on the optic lobes of the 

 brain or on the brain case iuid descended fartiier 

 by 3.9 nun., and tiu> cleitiirum had pigment along 

 its inner edge — the only changes since 3.2 mm. 

 By 4.0 mm., the spots on the developing caudal 

 fin and those on the ventral midline had dis- 

 appeared. In achlition tliere was loss of some 

 pigmentation on the preopercle, cleithrum, and 

 gill arch. This loss was complete at 6.6 mm., 

 except on the base of the preoperde-anglc spine 

 (fig. 10). 



Otlicr tluin a general darkening of tlie entire 

 outer surface, which obscured the internal pig- 

 mentation, no furfeiier changes were noted until 



