OCR Text |
Show 1887.] FROM THE ANDAMAN ISLANDS. 145 there are more than three pairs of holes ; from that species it is to be at once distinguished by the absence of the remarkably modified turciforrn spicules. On the whole, it stands nearest to H. scabra, but is distinguished by its speckled and less dense integument, and the absence of the median ventral groove. A specimen 160 millim. long has the greatest circumference 40; one 140 millim. is only 10 millim. round at the anus. Three smaller specimens differ from the more matured, two by a larger amount of orange in their coloration, and the third by the greater stiffness of the skin. HOLOTHURIA MARMORATA. I have had great difficulty in coming to a definite conclusion as to the name to be given to the specimens now associated as H. marmorata ; the complete absence of a circular disposition of the pigmentation prevents their association with //. argus; on the other hand, the comparatively small size of the oesophageal ring is against their affinity with H. marmorata. I believe the fact of the matter is that Dr. Theel is justified in his supposition that these two species and some others are but varieties or various stages of a variable and widely distributed species which grows to a great size. HOLOTHURIA PAPILLATA. (Plate XVI. fig. 8.) Twenty tentacles. Body elongated, may be wider in its hinder than in its two anterior thirds ; prominent scattered dorsal papillae, which are larger and more closely packed anteriorly than posteriorly ; five or more small papillae around the anus. Suckers on central surface only, arranged in two irregular rows, which unite posteriorly ; each sucker is placed on a yellowish papil-liform process. Colour dark slate-grey above, lighter below. Body-wall thin, the parts of the oesophageal ring are small, the ampullae long; one large Polian vesicle. Genital tubes short and numerous. Apparently no Cuvierian organs. The only calcareous deposits are in the form of stools (Plate XVI. fig. 8). Notwithstanding these numerous negative characters, the large size and well-developed papillae must make this a very conspicuous species. It may be 280, 320 long, and 60, 80 millim. broad. EXPLANATION OF PLATE XVI. Figs. 1-3. Moira stygia, xii- Fig. 1. With spines, and from the side. 2. Test denuded, to show the arrangement of the plates. 3. Test from above, to show the disposition of the ambulacra . 4. Spicules of Haplodactyla andamanensis. 5. Spicule of Pscudocucumis acicida. 6. Spicules of Holothuria albida. 7. Spicules of Holothuria cadelli. 8. Spicules oi Holothuria papillata. Figs. 4-8 X 500. PROC. ZOOL. Soc-1887, No. X. 10 |