File:American malacological bulletin (1986) (18156330385).jpg

Title: American malacological bulletin
Identifier: americanmal4519861987amer (find matches)
Year: 1983 (1980s)
Authors: American Malacological Union
Subjects: Mollusks; Mollusks
Publisher: (Hattiesburg, Miss. ?) : (American Malacological Union)
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Biodiversity Heritage Library

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EYSTER: NUDIBRANCH EMBRYONIC CAPSULES 209
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Fig. 7. Transmission electron micrograph of 14 day old Aeolidia papulosa (5°C) preveliger embryo in intact capsule. Neither the capsule wall nor the albumen (a) appear to contain carbohydrates oxidizable with periodic acid. The glycogen (arrows), which reacted with the periodic acid, appears electron dense. C= cilium. M= mitochondrion. Bar = 0.5 ^m. Aeolid nudibranchs are said to lack albumen (Ghiselin, 1965; Beeman, 1977). However, Kuzirian (1973) observed "albumen" in three coryphellid species and in the present study a granular substance presumed to be albumen was detected in the intracapsular fluid of three aeolids: Coryphella salmonacea (Figs. 4-6), Aeolidia papulosa (Fig. 7), and Her- missenda crassicornis (Fig. 10). With TEM, the precipitated material appears as electron dense granular material after exposure to glutaraldehyde, osmium tetroxide, uranyl acetate and lead citrate (Fig. 6). Clark ef a/., (1979) have reported similar condensation upon fixation for albumen of the sacoglossan opisthobranch Elysia cauze. The identification of this presumed albuminous material is not always certain. Although Kuzirian (1973) could detect albumen during passage of oocytes through the oviduct, once the capsule was fully formed, both the albumen and the capsule wall stained so similarly that it was impossi- ble to histochemically distinguish the two with light microscopy. In many TEM sections in the present study it was difficult to ascertain whether some of the observed granular material is part of the movable intracapsular fluid or an in- tegral part of the stationary capsule wall (Fig. 7). In the sacoglossan opisthobranch Costasiella lilianae the inner sur- face of the capsule wall is apparently lined with vesicles that are considered albumen and that break off and are consumed by the growing embryo (Clark and Goetzfried, 1978); the prevalence of this mode of potential embryonic nutrition among opisthobranchs is unknown. The composition of the intracapsular fluid and par- ticulates of nudibranchs has been examined histochemical- ly by Ghiselin (1965) and Kuzirian (1973). Ghiselin (1965) con- cluded that albumen was lacking in the aeolid Hermissenda crassicornis, and was composed of neutral carbohydrate in the dorid Dendrodoris albopunctata. Kuzirian (1973), in con- trast, determined that albumen was present in three Cor- yphella (Aeolidacea) species and was a weakly acidic sulfated

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