. Fresh-water biology. Freshwater biology. Sponge massive, though brittle and friable. Slieleton spicules slender, smooth, sharply pointed at both ends, nearly straight. Shaft of long birot- ulates almost smooth, slender, straight; rotules a circle of curved hooks, joined at the base. Short birotulates with stouter shafts, profusely, irregularly, and strongly spined; rotules not mark- edly convex in profile, irregularly, narrowly, and deeply serrated. Free spicules very minute, abundant, resembling those of Dosilia. Gem- mules large, spherical, with single, very small aperture having short, st
. Fresh-water biology. Freshwater biology. Sponge massive, though brittle and friable. Slieleton spicules slender, smooth, sharply pointed at both ends, nearly straight. Shaft of long birot- ulates almost smooth, slender, straight; rotules a circle of curved hooks, joined at the base. Short birotulates with stouter shafts, profusely, irregularly, and strongly spined; rotules not mark- edly convex in profile, irregularly, narrowly, and deeply serrated. Free spicules very minute, abundant, resembling those of Dosilia. Gem- mules large, spherical, with single, very small aperture having short, straight foraminal tubule. From Pinto Creek, Kinney County, Tex., and Shreveport, La.; one specimen measured 29 X 25 cm. Fig. 575. Asteromyenia plumosa. ^, gemmule show- ing aperture in center, X 35; B, short birotulates, X 120; C, long birotulates, X 120; D, free microscleres, X 120; £, skeleton spicule, X 120. (After 40 (39) Terminal spines of longer gemmule spicules distinctly recurved. Asteromeyenia radiospiculata (MUls) iS. Resembles A. plumosa. In profile the rays of the longer gemmule spicule have almost the form of a J. Ohio and Illi- nois. At Granite City, 111., specimens were taken from settling tanks of the city water works, measuring 42 x 12 X 8 cm. Fig. 576. mount.) Spicules oi Asteromeyenia radiospiculata. X 100. (From 41 (38) Dermal spicules acerate if present. Heleromeyenia Potts . 42 Spongillidae producing gemmules with birotulate spicules of two distinct classes, long and short. Margins of rotules not smooth but dentate or incised. 42 (43) Rotules of gemmule spicules of smaller class finely serrated. Heteromeyenia ryderi Potts 1882. Sponge massive, often hemispherical. Gemmules numerous, crust thick, foramina short and inconspicuous. Skeleton spicules grad- ually pointed, entirely spined except at the tips. Dermal spicules wanting. Shafts of long birotulates spined, rotules of three to six short recurved hooks, sometimes umbonate. Rotules of small b
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
