FISHERY BULLETIN: VOL. 73. NO. 2 



alamellar portion in the most ventral section of the 

 gonad, similar to that described by Smith (1965) 

 for some serranids. 



In the female, oogenesis takes place within the 

 lamellae. When the egg ripens, it breaks into the 

 central lumen, which leads to the common oviduct. 

 Some oocytes are interrupted in their normal 

 development and undergo a degeneration into 

 various types of corpora atretica (Figure 5). These 



During sexual transformation, crypts of 

 developing spermatocytes appear, first at the base 

 of the ovarian lamellae, and then throughout the 

 gonad (Figure 7). Unshed eggs and nonvi- 

 tellogenic (stage 2) oocytes are gradually reab- 

 sorbed and the number of lamellae visible in 

 cross-section are reduced. The basic structure of 

 the gonad remains ovarian, with a central lumen 

 into which the lamellae protrude. The lumen 



Figure 5.-Degenerating oocytes (doc) in the lumen of a resting ovary of Pimelometopon 

 pulchrum. Specimen number PP411, 217 mm SL. 



have been described briefly for serranids by Smith 

 (1965) and in detail for Monopterus albus by Chan 

 et al. (1967). Chan and his colleagues discuss the 

 possible endocrine function of atretic structures, 

 and state that all types of corpora atretica even- 

 tually end up as brown or yellowish bodies which 

 are long lasting in the gonad. In P. pulchrum, 

 brown bodies can usually be found near the gonad 

 wall and in the central portion of the lamellae. 

 Judging from the number of these terminal phase 

 corpora atretica in resting (class 2) females com- 

 pared with the usually greater number of earlier 

 stage atretics (Chan et al. 1967) in postspawning 

 females, the brown bodies are probably formed 

 from more than one degenerating oocyte. 



Brown bodies are also found in male gonads; 

 some of these are almost certainly the result of 

 oocyte degeneration in the previous female phase 

 (Figure 6), while others may be the result of 

 degeneration and coalescence of unshed sperm. 



however no longer functions in gamete transport 

 and sperm are collected in a series of sinuses on the 

 periphery of the gonad, reaching the outside by 

 means of ducts in the wall of the now unused 

 oviduct. This is very similar to the anatomy 

 described by Reinboth (1962, 1970) for other labrid 

 secondary (sex- re versed) males. No testes of the 

 primary type were seen. 



Transformation Schedule 



To illuminate the life history patterns of the 

 California sheephead populations, the gonad 

 development classes were grouped in the following 

 way: 



Immature: Class 1 only. 



Female: Classes 2, 3, and 4. 



Transitional: Class 5 only. 



Male: Classes 6, 7, and 8. 



The distribution of sexual types by standard 



268 



