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To elucidate sexual differences in gonad size and color in sympatric two sea urchins (Strongylocentrotus nudus and Hemicentrotus pulcherrimus), we examined S. nudus and H. pulcherrimus with gametes in the gonads, in the Sargassum yezoense bed in the Oshika Peninsula, northern Honshu, Japan during July-November and September-June, respectively, from 2008 to 2010. The changes in the gonad indices of H. pulcherrimus in the Sargassum bed were compared with those in the Undaria pinnatifida and Saccharina japonica kelp bed, using a data set obtained from Ogasawara et al. (2011). The gonad indices, by sex, of S. nudus rapidly decreased from September to a minimum in November, while those of H. pulcherrimus decreased from October to a minimum in December, February or April. For both species of sea urchin, the proportion of brown-colored gonads increased with a decrease in the gonad indices during spawning. A significant positive correlation between brown-colorization and gonad size was also detected. In H. pulcherrimus, the female gonad size was smaller than that of males during the spawning stage in both the Sargassum bed and the kelp bed. Gonadal re- growth of females during post-spawning was much slower in the Sargassum bed.

The messenger RNA for a beta-crystallin polypeptide with a molecular size of 27 kilodaltons, first detected 5 to 10 days after birth in the normal mouse lens and the Nakano mouse cataract, was not detected in the Philly mouse cataract with translation in vitro. The heterozygous Philly lens had intermediate levels of the 27-kilodalton beta-crystallin polypeptide and exhibited delayed onset of the cataract. The deficiency of functional 27-kilodalton beta-crystallin messenger RNA is the earliest lesion reported yet for the Philly lens and points to a transcriptional or posttranscriptional developmental defect in this hereditary cataract.