File:American malacological bulletin (1986) (17533728564).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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D'ASARO: EGG CAPSULES OF SMALL MARINE PROSOBRANCHS 191
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Fig. 2. Views of prosobranch egg capsules prepared with reflected and transmitted light. Magnification bars = 0.2 mm. (a) Smaragdia viridis viridemaris, apical view, (b) S. v. viridemaris, side view, (c) Littorina mespillum, apical view, (d) L. mespillum, side view, (e) Alvania aubehana, side view after expansion of innermost lamina, (f) Rissoina catesbyana, apical view, (g) R. bryerea, apical view, (h) R. bryerea, side view, (i) Zebina browniana, apical view, (j) Z. browniana, side view. capsule was in the basal disk, where a flaring edge marked its widest point (Figs. 2c, d). From this point, the sides of the disk tapered very gradually across its width and then tapered abruptly to form a dome. Most capsules had a ridge or ring around the apex of the dome (Fig. 2d). A single embryo (average diameter = 0.11 mm), enclosed in an ovarian mem- brane and surrounded by albumen, was centrally positioned within the viscous capsular fluid. Of the species described by Borkowski (1971), Pilkington (1971), and Bandel (1974), L. mespillum capsules resemble most closely those of L. meleagris and Melarpha cincta (Quoy and Gaimard, 1833). Both species have domes with one more encircling ridge or ring than L. mespillum, as well as having flatter apexes. Bandel (1974) suggested that Lewis' (1960) descrip- tion of Puperita pupa capsules actually referred to L. mespillum. Lewis' figure of specimens from Barbados had a narrower and curved basal disk and a less prominent dome than seen in the material from Bimini. Lewis reported that planktotrophic veligers hatched after two days. As with Puperita pupa, egg capsules or swimming veligers of Littorina mespillum can be released from splash pools only when flooded by storm-driven waves. Alvania aubehana (Orbigny, 1842) (USNM 836984) This West Indian rissoid, which is abundant in seagrass beds, paired and spawned from February through May, 1985. When given a choice of substrata for oviposition (Laurencia poitei) and other rhodophytes, Halodule wrightii, calcium carbonate, and the culture dish), 93% (N = 13) selected sites either in a bifurcation of an algal thallus or on

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