Philosophical Transactions of the Royal Society of London Volume 165, PT. 2 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1876 Excerpt: ... scattered tentacles resembling those of the hydranth, but much smaller; and where the tentacles cease to be borne the gonophores (b, b, b) commence, and continue with an irregular scattered disposition to within a short distance of the attached end of the blastostyle. The structure of the blastostyles resembles, in all essential points, that of the hydranth, with the exception of their being entirely deprived of a mouth. Their gastric cavity communicates with that of the hydranth which bears them; the villi-like processes of the endoderm are extremely well developed, and the spherical cells, loaded with brown granules, which enter into the composition of these processes are very abundant (Plate 57. fig. 14, a). The muscular lamella is well developed, and the structure of the tentacles is quite the same as in the hydranth, the rod-like tissue and pedunculated capsules being similar in both. The claspers (Plate 55. fig. 2, c, c, c, and Plate 57. fig. 14, b, b), as already mentioned, are long tentacle-like organs of a cylindrical form, slightly enlarged towards their distal extremity, where they terminate in a sucker-like disk. They spring, like the blastostyles, from the body of the hydranth, and mostly in pairs from two points close to the base of a blastostyle. They have, however, no definite arrangement; many blastostyles have no claspers at their base, and solitary claspers occur, not only at the base of a blastostyle, but here and there at some distance from it on the body of the hydranth. The claspers are very contractile. Their structure differs considerably from that of the blastostyle. The endoderm (Plate 56. fig. 11, a) is composed of an external layer of closely applied large cells with clear contents, and an internal looser layer of small round c...