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Show 238 DR. J. E. G R A Y O N Z O A N T H I N ^ E . [Feb. 14, and those on the lip and the edge of-the shell are generally the largest, as they are in a position where they can obtain the most nourishment. They are gradually developed from the surface of the coral that covers the shell. They first appear as a small circular spot, which enlarges and gradually raises itself above the surface of the surrounding coral until it forms a cylindrical body, which is generally considerably higher than it is broad. The adult or well-developed body sometimes breaks off from the base, leaving a circular concave scar, with pores round its circumference, which is the basis of the ovaries of the animal. 4. GEMMARIA, Duchass. & Michel. Mem. Coral, des Antilles, 55. Mammillifera, sp. Palythoa, sp., Milne-Edw. Coral, i. 303. Base expanded; polypes not soldered together. Duchassaing and Michellot describe several species of this genus; to these add GEMMARIA? SULCATA. Zoanthus sulcatus, Gosse, Brit. Sea Anem. 303, t. 9. f. 7,1.12. f. 2. Hab. Devonshire. Tentacles twenty-two, in two rows ; upper half of polypes naked. 5. PALYTHOA, Lamx. Hist. Polyp. 361 ; Duchassaing & Michellot, Me'm. Coral, des Antilles, 53, 1860. Palythoa A A & A A A , Milne-Edw. Coral. 304. Cavolina, sp., Schweiger. Corticifera, Lesueur. Mammillifera, Ehr., Blainv. The polypes soldered side by side. 1. PALYTHOA MAMMILLOSA, Lamx. L. stellata, Lamx. Alcyonium mammillosa, Solander, Zooph. t. 1. f. 4, 5. 2. PALYTHOA AXINELLA, O. Schmidt, Sponges of the Adriatic, p. 61, t. 6. f. 1,2. Polype short, broad, on an expanded base, white when dry. Hab. Adriatic. Parasitic on Axinella cinnamomea and A. verrucosa, O. Schmidt (Sponges of the Adriatic, pp. 61, 62). Esper called the latter sponge Spongia verrucosa, from the presence of this polype. Professor Oscar Schmidt described a species of Axinella which has circular eight-rayed stars scattered on the surface and sunk in the substance of the sponge, under the name of Axinella polypoides (p. 62, t. 8. f. 5). He calls these stars oscules; but they are very Unlike the oscule of any other sponge, and I think they may be parasitic actmioidpolypes. Mr. Bowerbank, in his • British Sponges' (t. 20. f. 307), figures a very similar body, which he describes as 1 |
