American malacological bulletin (1986) (17533747664)

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

Text Appearing Before Image:

208 AMER. MALAC. BULL. 4(2) (1986) for carbohydrates (ThieVy, 1967; Porter and Rivera, 1979), material associated with the microtubules was periodate reac- tive (Fig. 3). Little to no periodate reactive substances were detected in the sperm keel (Fig. 3). These observations in- dicate that the sperm did not decay although their glycogen (energy) supply was apparently exhausted. The third and last internal component of the capsule is the fluid (and sometimes particulates) lying between the developing embryo and the inner surface of the capsule wall. As the embryo develops cilia, it moves freely within this fluid. In some species the untreated fluid is reported to look granular rather than clear and it is this granular material that is sometimes referred to as albumen. We do not know if un- treated albumen is always granular in appearance or how the presence of albumen varies with taxon, development type, or egg diameter. For sacoglossan opisthobranchs, Clark and Jensen (1981) reported three types of albumen: fine granular albumen ( < 1 /tm diam.), frothy ( = alveolar) albumen, and vesicular albumen (up to 10 ^m diam., usually attached to inner capsule wall). In the opisthobranch Phyllaplysia taylori, Bridges (1972) reported the presence of a large intracapsular body (49 diam.) that she believed was food for the em- bryo. In this paper I will use the term albumen to refer to any condensed, granular material, regardless of its chemical com- position, observed with TEM or SEM, between the embryonic surface and the capsule wall.

Text Appearing After Image:

Figs. 4-6. Electron micrographs of intracapsular albumen in the aeolid nudibranch Coryphella salmonacea. Fig. 4. SEM of 3V2 week old embryo fixed and dried after manual excapsulation. Albumen was washed away from the embryonic surface. Bar = 100 nm. Fig. 5. SEM of 7 week old embryo fixed and dried while still inside intact capsule. An obvious layer of flocculent albumen precipitated from the intracap- sular fluid is observed on the embryonic surface after the capsule (C) is broken away. Bar = 100 ^m. Fig. 6. TEM of material lying between surface of 7 week old embryo and inner wall of intact capsule. The abundant granular material (arrowheads) is believed to be albumen. One sperm cross-section is shown at left (*). Bar = 1.0 ^m.

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1986

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