| OCR Text |
Show 1887.] FROM THE ANDAMAN ISLANDS. 143 conclusions formulated by Mr. Alex. Agassiz in his ' synonymy ' of this species. The larger specimens collected are magnificent examples of this interesting species. MOIRA STYGIA. (Plate XVI. figs. 1-3.) Being in some doubt as to whether I had before me the species described by Dr. Liitken, I sent the drawings here given to that accomplished zoologist with the request that he would compare them with the type in the Copenhagen Museum. Dr. Liitken writes :- " The specimen from Zanzibar is much smaller than your figure [which bore the mark x 1-j] - 2 4 mm. in length and 14 m m . in height. The anterior lateral ambulacra are more bent, the posterior shorter than in your figure ; the posterior excavation of the shell below the periproct less crested than in your figure. But these differences might be those of age." The most striking difference to which this obliging communication directs attention is the great difference in the proportion of height to breadth ; however, in a specimen from an unknown locality, which I am inclined to place also in this species, the proportion of height to length is about the same, for it is as 37 to 30, whereas in the Andaman species it is as 33-5 to 27 ;and the very same is true also of the specimen whose dimensions are given in the ' Revision of the Echini,' where the height is to the long diameter in the ratio of 40 to 49'5. The other dimensions of the Andaman specimen are:-Breadth 28'5; length of antero-lateral ambulacrum 13; of the posterolateral ambulacrum 10 ; length of anal area 4 ; breadth of do. 3 millim. It is now for the first time figured, and is the first specimen of the genus that has been shown with the spines on. The discovery of this species at the Andamans extends its range, though not indeed in any unexpected way ; hitherto specimens have been known only from the Red Sea and Zanzibar. HOLOTHURIOIDEA. H A P L O D A C T Y L A ANDAMANENSIS. (Plate XVI. fig. 4.) Body elongated, tapering posteriorly ; the skin of a slightly reddish-grey hue, darker above than below. Tentacles ? (retracted). The body-wall is thin; the ossicles of the oesophageal ring are elongated, rather stout, deeply grooved on the outer surface; the radials are longer than the interradials, and have a bifurcated distal tail. One Polian vesicle. Genital tubes numerous, long, well developed, purple in colour. Lungs extend to anterior end of body, two well but unequally, and one poorly developed lung-trunk ; the last does not extei.d far forwards. Biscuit-shaped or dumbbell-like spicules (Plate XVI. fig. 4). By the forms of its spicules it is distinguished easily from H. mol-padoides, and by them and the tapering of the hinder end from H. australis. |
