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Show 130 MR. C. W. ANDREWS AND OTHERS ON THE [Feb. 20, their shape is subspherical, elongated or pyriform, and they vary in size from 1 to 5 c.c. in length or diameter, and in colour from yellow to dark brown. The alcohol specimens are much skrunken and corrugated, the surface being marked with polygonal or elongated depressions ("wabige vertiefungen," 0. Schmidt) with pigmented stellate markings. The specimen in formol, which was unfortunately transferred to alcohol, was bluish-black and quite smooth. On drying, the surface has a distinctly gritty appearance, caused by the shrinking of the dermal membrane on the foreign particles beneath. The foreign bodies (fine sand-grains, sponge-spicules) form a fairly-well defined layer in the cortex and just beneath the dermal membrane; in one specimen spicules projected beyond the surface at right angles. There are no foreign bodies scattered in the interior of the body, differing in this respect from the specimens from Algiers described by O. Schmidt. Distribution. Mediterranean ; Atlantic ; Christmas Island. CHONDRILLA NUDA Lendenfeld. 1867. Chondrilla nuda Lendenfeld (9. p. 105, pl.x. figs. 69-71). One small specimen of this species occurs in the form of a rounded bilobed mass 8 x 9 x 4 m m . in size, growing on Chondrosia plebeja. The surface is bluish-black and smooth, and shows under a lens a faint whitish reticulate pattern. The larger lobe has two minute raised oscules "3 ram. in diameter. The cortical layer includes columns of large granular pigmented cells, as in the specimen from Zanzibar. The spicules are slightly larger than in Lendenfeld's specimens. The oxyasters, 30 p in diameter, possess 8 sharp spines usually slightly curved. The spherasters, 25 p in diameter, possess 25- 30 sharp-pointed pyramidal prickles. In the Zanzibar specimens the oxyasters are 22-30 p, and the spherasters only 10-12 p in diameter. Distribution. Zanzibar; Christmas Island. SIDONOPS PICTETI Topsent. 1897. Sgdonops picteti Topsent (18. p. 431, pi. xviii. fig. 2). 1898. Sidonops picteti Lindgren (10. p. 349, pi. xviii. fig. 17, pi. xx. fig. 6). There are four small specimens, the largest of which is 5 c.c. by 2 c.c. in area and 1*5 c.c. in thickness. Several small spherical buds about 2 m m . in diameter are lightly but closely attached by bundles of oxeote spicules. When a bud is detached, a shallow circular depression remains, the sterrastral crust here being thin and biconcave in section. The slender cortical oxeas and the oscular palisade of spicules described by Lindgren are present. Distribution. Amboina ; Java ; Christmas Island. |