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Show 298 MR. F. P. BEDFORD ON MALAYAN ECHINODERMS. [MAR. 20, 15. RETASTER CRIBHOSUS. Pteraster cribrosus, von Martens, Arch. f. Naturg. 1867, p. 109, Taf. iii. fig. 2. Retaster insignis, W . P. Sladen, ' Challenger' Reports, vol. xxx. Asteroidea, 1889, p. 482. References. M. Sars, Ofv. af Norg. Ech. Christiania, 1861, tab. 4. J. 0. E. Perrier, Revision des Stellerides, 1875, p. 383. L. Doederlein, Semon's Zool. Forsch. in Austr. & c Bd. v. Lf. 3, 1896, p. 319. Locality. Four specimens, two of which are quite young, in 10-15 fathoms, Singapore. Distribution. Zanzibar, Mozambique, Ceylon, Philippines, A m boina, Samoa (Doederlein). The largest specimen agrees with Dr. Doederlein's description of a specimen from Amboina. The colour, when alive, of all four specimens was bright brick-red, but they rapidly become colourless in spirit; when alive, the osculum can be seen to open and close with a fairly regular rhythm of about once every ten seconds. Sars has given an account in Pteraster militaris of the osculum bounded by five lappets and of the cavity into which it leads, situated between the dorsal membrane aud the true abactinal surface of the body, and in direct communication with the exterior by a large number of short straight tubes in the former and lined by a columnar epithelium; it appears to function in both sexes as a respiratory chamber, and secondarily in the females as a brood-pouch ; but my want of knowledge of Norwegian has prevented me from understanding Sars's paper as much as I should have wished, but the relations appear to be the same in this species. The reticular arrangement of muscle-fibres in the dorsal membrane is only apparent under a microscopical examination. In additiou to these 15 species there were two species of Asteri-nidce, each represented by a single specimen. I cannot identify them as belonging to any known species; but as they both appear to be young forms, it seems advisable to defer description until a later date, when a fuller series may be obtainable: they belong to the genera Patiria and Asterina respectively. EXPLANATION OF THE PLATES. PLATE XXI. Fig. 1. Ehabdociclaris annulifera, p. 274. a. Spines from an interainbulacrum of specimen No. 1. Nat. size. "• >> >> H Mo. 2. Nat. size. c- " » >i No. 4. Nat. size. **• Jr " >> » No. 6. Nat. size. (Vide table of measurements in text, p. 276.) The spines are so arranged that the uppermost in each series is that which lies nearest to the calycinal system of the test, the lowermost being that which borders on the actinostome; they are also laid flat, so that their basts lie next to the adjacent ambulacrum, their points being directed towards the centre of the interambulacrum ; no attempt has been made |