18S7.] 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 U] — 24 mm. in length and 14 mm. 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 21 ; and tiie very same is true also of the specimen 

 whose dimensions are given in the ' Revision of the Echini,' where 

 the height is to the Ion"; 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 postero- 

 lateral 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. 



HOLOTHTIRIOIDEA. 



Haplodactyla 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 exteid far forwards. Biscuit-shaped or dumbbell-like 

 spicules (Plate XVL fig. 4). 



By the forms of its spicules it is distinguished easily from //. mol- 

 padoides, and by them and the tapering of the hinder end from H. 

 australin. 



