C *miM 



FIGURE 1. — Photomicrographs of Sardinops sagax postovulatory follicles. (A) Day 0, showing highly convoluted morphology. Note 

 cluster of eosinophilic granules I arrow) in lumen 1 250 x ). (P>i Day 0, showing columnar epithelial cell lining (arrow) (400x ). (C)Day 

 1. columnar epithelial cell lining (arrow) undergoing degeneration. Underlying layer is connective tissue theca (400 x ). (D) Day 2, 

 lumen contains scattered degenerated columnar epithelial cells ( arrow i (400 x ). 



should be some suggestion of it. We therefore rec- 

 ommend careful observation of the convoluted 

 structure of day-0 and day-1 structures before at- 

 tempting to identify day-2 structures. 



A useful criterion for distinguishing day-2 S. 

 sagax postovulatory follicles from advanced atre- 

 tic follicles would be the presence of yellow 

 granules (irrespective of staining) that are found 

 in advanced atretic structures (delta atresia) 

 (Lambert 1970). These were occasionally noted in 

 S. sagax. The presence of these yellow granules 

 which appear in nucleated clusters conclusively 

 indicates atretic structures. 



We did not use the artificial spawning technique 

 (Leong 1971) for aging postovulatory follicles in S. 

 sagax. However, we feel that estimating their age 

 from periodic collections of fish, after the spawn- 

 ing time is established from collections of egg 

 samples (as done herein), will prove to be a useful 

 alternative method. This is particularly true in 

 situations where facilities are lacking for 



laboratory-induced spawning. Laboratory- 

 induced spawning studies using S. sagax will be 

 useful to provide estimates of the accuracy of our 

 classification scheme. 



While there are numerous accounts of the oc- 

 currence of postovulatory follicles in marine 

 fishes, there are few reports describing their 

 longevity and subsequent degeneration. They 

 have been described previously as being short- 

 lived structures by Yamamoto and Yoshioka (1964) 

 and Hunter and Goldberg (1980). More studies are 

 needed of a wide variety of fishes before our 

 knowledge of their histology and function is com- 

 pleted. Of utmost value will be investigations on 

 how to distinguish conclusively between old post- 

 ovulatory follicles and old atretic follicles. 



Acknowledgments 



We thank J. R. Hunter and B. J. Macewicz for 

 their constructive comments. 



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