The Fauna of British India, including Ceylon and Burma / edited by A.E. Shipley. Freshwater sponges, Hydroids & Polyzoa / by N. Annandale.

Date:
1911
Catalogue details

Licence: In copyright

Credit: The Fauna of British India, including Ceylon and Burma / edited by A.E. Shipley. Freshwater sponges, Hydroids & Polyzoa / by N. Annandale. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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    moderate, flat, surrounded by deep, cone-shaped collars ; radiating furrows and canals in the parenchyma surrounding them often deep. External pores contained normally in single cells. The surface frequently covered hy small rounded buds; true branches if present more or less flattened or conical, always short, as a rule absent. Skeleton loose, feebly reticulate at the base of the sponge; trans- verse fibres slender in the upper part of the sponge, often scarcely recognizable at its base. Very little spongin present. Spicules. Skeleton-spicules long, smooth, sharply pointed; the length on an average at least 20 times the greatest breadth, often more. Elesh-spicules slender, gradually pointed, nearly straight, covered with minute straight or nearly straight spines. Gemmule- spicules very similar, but usually a little stouter and often blunt at the ends; their spines rather longer than those on the fles'u- spicules, usually more numerous near the ends than in the middle of the spicule, slightly retroverted, those at the extreme tips often so arranged as to suggest a rudimentary rotule. Fig. 9.—Gemmule of Spongilla proliferens as seen in optical section (from Calcutta), X 140. Gemmules usually numerous, lying free near the base of the sponge, very variable in size, spherical, suiTounded by a thick granular layer in which the spicules, which are always very numerous, are arranged tangentially, their position being more near the vertical than the horizontal; a few horizontal spicules usually present on the external surface of the gemmule, which frequently has a ragged appearance owing to some of the tangential spicules protruding further than others. Foramina] tubule stout, cylindrical, usually somewhat contorted; its orifice irregular in outline. Sometimes more than one foramen present.