POWELL and GORDY: EGG AND LARVAL DEVELOPMENT OF THE SPOT 



Early Stage Eggs 



Pigment was never observed on the embryo or 

 oil globule of early stage eggs. By the end of the 

 early stage, when the blastopore was reduced to a 

 small opening, optical vesicles were discernible, 

 there were no visible myomeres, and the oil 

 globule was situated adjacent to the blastopore, 

 slightly posterior to the tail. 



Middle Stage Eggs 



Pigment first appeared on the embryo and oil 

 globule during the middle stage (Figure lA). 

 Melanophores, which were mainly punctate, were 

 scattered on the dorsal and lateral surface. Pig- 

 ment was sparse or missing from the snout and on 

 the posterior one-fourth of the body and was never 

 present near the notochord tip. Melanophores ap- 



peared to be most dense in an area about one-third 

 the body length from the snout. At the end of the 

 middle stage, dendritic melanophores were more 

 common and the pigment pattern was transitional 

 from that illustrated for middle and late stage 

 embryos (Figure 1). Also at this stage melano- 

 phores were relatively more dense on the dorsal 

 surface of the head just posterior to the eyes and 

 appeared to migrate laterally to form, eventually, 

 a longitudinal row of dorsolateral melanophores. 

 Initially, melanophores occurred on the posterior 

 surface of the oil globule, but by the end of the 

 middle stage they were located on the anterodor- 

 sal surface. 



Late Stage Eggs 



The embryos of late stage eggs developed a 

 characteristic pigment pattern ( Figure IB) similar 



Figure l. — Eggs of Leiostomus xanthurus: A, middle stage; left, the anterior part of embryo, right, the 

 posterior part of embryo; B, late stage: left, the anterior part of embryo, right, the posterior part of embryo. 



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