FISHERY BULLETIN VOL 77, NO, 1 



Table 2, — Measurements of eggs of Pleuronichthy^ species, Hypsopsetta guttulata, and HippogLossina stomata, including 



Synodus lucioceps for comparative data. 



1.20 to 1.56 mm; and those of P. uerticalis, from 

 1.00 to 1.16 mm. Although eggs of P. ritteri, rang- 

 ing in diameter from 0.94 to 1.08 mm, fall within 

 the size range of P. verticalis. they can be readily 

 distinguished by the presence of a small oil 

 globule, 0.08-0. 14 mm in diameter. Eggs of P. ocel- 

 latus were unavailable. 



Differences in mean diameter of P. coenosus 

 eggs were noted by locality, with eggs taken in 

 open waters off the coast having a larger mean 

 diameter and standard deviation (Table 2, Cal- 

 COFI collections) than eggs sampled from the 

 inlet of a small, shallow, manmade harbor near a 

 power plant discharge (Table 2, King Harbor sam- 

 ples). Except that they are often slightly larger in 

 size, early- and middle-stage eggs of P. coenosus 

 are difficult to differentiate from Synodus 

 lucioceps eggs. They can be separated, however, by 

 careful examination of the size and arrangement 

 of polygons on the chorion. The mean of the 

 greatest distance across polygons (sample 

 size = 200 polygons) on P. coenosus eggs is 0.035 

 mm in contrast to 0.047 mm for S. lucioceps eggs 

 (Table 3). Furthermore, the polygons on P. 

 coenosus eggs are more regular in arrangement 

 than on S. lucioceps eggs (Figure 1). This more 

 uniform compacting of smaller polygons on P. 

 coenosus eggs versus a more random patterning of 

 larger polygons on S. lucioceps eggs is visible 

 under a light microscope, and will separate these 

 eggs. Late-stage eggs are easily distinguished by 

 the heavy pigmentation on the embryo of P. 

 coenosus compared with the sparse pigment on 



Table 3, — Comparison of polygon size on chorion of eggs of 

 Pleuronichthys and Synodun lucioceps. 



advanced S. lucioceps embryos, which also have a 

 longer gut. 



The arrangement of polygons on the chorion of 

 eggs of the other three species of Pleuronichthys 

 from the eastern Pacific is similarly uniform (Fig- 

 ure 2). The polygons are somewhat larger on the 

 chorion of eggs of P. decurrens and P. verticalis 

 than P. coenosus, averaging ca. 0.042 mm in both 

 species (Table 3). Interestingly, Budd ( 1940) gave 

 the identical value, 0.042 mm, for this measure- 

 ment on eggs of these two species. The polygons 

 are smaller on eggs of P. ritteri. averaging 0.030 

 mm. 



The eggs of P. cornutus were described by Mito 

 ( 1963) and Takita and Fujita ( 1964). Mito gave the 

 egg diameters as 1.16-1.26 mm, the oil globule as 

 0.016-0.020 mm. Takita and Fujita gave similar 

 measurements for the hexagonal meshes of 0.018 

 mm, but gave a smaller egg diameter of 1.03-1.11 

 mm. 



Hypsopsetta guttulata 



Orton and Limbaugh (1953) obtained running 

 ripe eggs of//, guttulata by stripping ripe adults 

 and obtained similar eggs from plankton collec- 

 tions. The eggs were notable in that they con- 

 tained a conspicuous, moderately large oil globule. 

 This was the first record of an oil globule in eggs of 

 flatfishes of the family Pleuronectidae, subfamily 

 Pleuronectinae. The egg capsule was simple, 

 without polygonal sculpturing or other apparent 

 texture; the yolk was homogenous. Orton (1953) 

 gave a fairly detailed description of pigment de- 

 velopment on embryos of//, guttulata. Neither of 

 the above papers contained information on egg 

 size. Eldridge (1975) reported a mean egg diame- 

 ter of 0.80 mm with usually one oil globule of 0.14 

 mm in mean diameter and numerous other small 

 oil globules in the yolk. Eggs in our samples had a 

 mean diameter of 0.84 mm (range 0.78-0.89 mm) 

 with a single oil globule averaging 0.13 mm in 



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