. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. 852 Mr. H. J. Carter on the Reproductive side and on the other, or outside, in continuation with the beaks of the spongozoa (woodcut, d) ; while the germinal vesicle which is spherical, averages 2-6000ths in. in diameter, and the germinal spot, which is circular and opaque, about l-6000th in.; so that the interval between the ovum and outer border of the ampullaceous sac is filled up by the spongozoa (a). Now, when the ovigerous portion of the sponge is torn to pieces for micr
. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. 852 Mr. H. J. Carter on the Reproductive side and on the other, or outside, in continuation with the beaks of the spongozoa (woodcut, d) ; while the germinal vesicle which is spherical, averages 2-6000ths in. in diameter, and the germinal spot, which is circular and opaque, about l-6000th in.; so that the interval between the ovum and outer border of the ampullaceous sac is filled up by the spongozoa (a). Now, when the ovigerous portion of the sponge is torn to pieces for microscopic examination many of the ova become detached or separated, and tlien they are seen to be fringed circumferentially with the filamentous remains of the beaks of the spongozoa, which, radiating from them all round, kept the ovum in position within the ampullaceous sac {d).. ff, oTTim as seen under deep focussing, in wliicli tlie spongozoa surrounding it are only visible ; h, ovum under less deep focussing, in wbicli the whole of the spongozoa covering the ovum come into vieAv; c, oviun in the cell of the ampullaceous sac without any spongozoa; d, ovum out of the ampullaceous sac, showing the capsule with shreds of bealis of spongozoa attached to it. There is no difficulty whatever in seeing all this clearly in a well-preserved specimen when the sections are thin and mounted in glycerine, especially when stained. Every ampullaceous sac on the inner portion of the sponge (where the ova are, as usual, chiefly developed) contains a single ovum about the size mentioned, and on no occasion have I observed more than one, nor have I been able to dis- tinguish anything like a spermatoid development. I state this because hereafter I shall have to notice another specimen of the same species in which there appears to be a spermatoid development without any ova. It must therefore be inferred that in this instance the ovum is developed loitliin the ampullaceous sac, that it originated t
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