THE OPHIUEID^ OF THE MERGUI AECHIPELAGO. 



85 



Ou the Ophiuridse of the Mergui Archipelago, collected for the 

 Trustees of the Indian Museum, Calcutta, by Dr. John 

 Anderson, F.R.S., Superintendent of the Museum. By 

 Prof. P. Martin Duncan, M.B. Lond., F.K.S., F.L.S. 



[Eead 3rd June, 1886.] 



(Plates VIII., IX., & XI. figs. 28-40.) 



Contents : — I. Introduction. II. List of the Species. III. Descrip- 

 tion of the Species. IV. Remarks on the Species. V. Description of 

 the Plates. 



I. Introduction. 



The species of Ophiuridse which form the subject of this com- 

 munication were handed over to me by Dr. Anderson for 

 description and classification. 



The little fauna is rich in individuals, and some are of consi- 

 derable dimensions. There are thirteen species, besides some 

 young forms of the genus Ophioglypha, in the collection, and 

 four of them have been recorded from other localities. The latter 

 are, with one exception, well-known species ; they are Ophio- 

 lepis cincta, Mull. & Trosch., Ophiocorna scolopendrina, Lmk. sp., 

 Ophiocnemis marmorata, Lmk. sp., and Ophiotlirix Martensi, 

 Lyman. These forms are characteristic of the Indian Ocean and 

 the western Pacific Islands. The first extends to the Philippines, 

 the second ranges from the Cape of Good Hope to the Philip- 

 pines and Pijis, the third has been found in Ceylon and in the 

 Great Ocean, and the fourth is from the Philippines. None of 

 the Korean species are present ; and one Ophiothrix is closely 

 allied to a species from the Nicobars. 



All the species are shallow-water dwellers ; and some of the 

 individuals appear to have suffered from a deficiency of carbonate 

 of lime in their food. 



There are some remarkable forms amongst the collection, and 

 especially the new species of OpJiiolepis and the new genus Ophio- 

 campsis, represented by one species, which is allied to Ophio- 

 psammium and Ophiothrix. The species of Ophiothrix gave much 

 trouble in their classification ; and the structures of Ophiothrix 

 variabilis have been of necessity carefully studied. Their de- 

 scription forms the subject of a special communication, which 

 follows this. 



