. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 436 J. F. HARRK'iAX AND D. L. ALKON = X. DAYS SURVIVAL FIGURE 3. Regression of number of egg masses deposited on days survival. rations from wild individuals weighing 34 mg ( cm body length). Egg production in individuals from wild populations is estimated to begin at about months post-metamorphosis and continue until death at 5-8 g, four months post-metamorphosis. Both the total number of egg masses produced and the age at which egg-laying commences depend on age at ini
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 436 J. F. HARRK'iAX AND D. L. ALKON = X. DAYS SURVIVAL FIGURE 3. Regression of number of egg masses deposited on days survival. rations from wild individuals weighing 34 mg ( cm body length). Egg production in individuals from wild populations is estimated to begin at about months post-metamorphosis and continue until death at 5-8 g, four months post-metamorphosis. Both the total number of egg masses produced and the age at which egg-laying commences depend on age at initial copulation. DISCUSSION Hermissenda crassicornis is one of several nudibranch species which have been reared through metamorphosis in the laboratory (Bonar and Hadfield, 1974; Thompson, 1958, 1962, 1967; Tardy, 1970; Perron and Turner, 1977; Harris, 1975). Harris (1975) and Perron and Turner (1977) have successfully reared nudibranch species having planktotrophic (feeding) larvae from egg to egg. Other nudibranch species reared have been either lecithotrophic or direct de- velopers. Hermissenda has a longer obligatory planktotrophic stage, 34 days, than either Phcstilla melanobranchia Bergh 1874 (Harris, 1975) or Doridclla obscura Verrill (Perron and Turner, 1977). The length of the veliger stage in Hermissenda is similar to that reported for five species of Pacific aplysiid opisthobranchs, 30-34 days (Kriegstein, Castellucci, and Kandel, 1974; Switzer-Dunlap and Hadfield, 1978). Switzer-Dunlap and Hadfield (1978) observed a plateau in shell growth before metamorphosis in four aplysiid species similar to that noted in Hermissenda. As adults, three of the four above mentioned aplysiid species were reported to grow to a larger size in the laboratory than in the field. No specimens of Hermissenda fed in the laboratory have exceeded the maximum size of wild individuals. Stages in the life cycle of Hermissenda follow in the same sequence as the seven general life history stages
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
