A. H.CLARK: THE CRINOIDS OF THE INDIAN OCEAN. 25 



approximately the equivalent of the thalassometrid genus Thalassometra. It is 

 in the genus Pachylometra that each extreme of depth is found, one species 

 occurring in 30 fathoms, another in 1,200. The remaining four genera, Ghloro- 

 mefra, Poecilometra, Strotomdra, and Gharitometra, each composed entirely of ten- 

 armed species, and including between them only nine of the 28 East Indian species, 

 are only found between the Meangis Islands and southern Japan in water of 

 between 95 and 630 fathoms in deptli. 



Anfedoniche . 



Strictly speaking, the family Antedonidse as at present constituted is the 

 macrophreate equivalent of all the oligophreate families combined, each of its 

 subfamilies being in reality comparable to an oligophreate family ; but these 

 subfamilies must be united under one general family heading in order properly 

 to show the relationships of the Pentametrocrinidae and Atelecrinidae, both of 

 which are closely akin to the true antedonid type, yet differ profoundly from it 

 in fundamental points of structure. Species of the Antedonidse occur everjrwhere , 

 on all shores, in the warmest and coldest water, and from between tide marks 

 down to 2^900 fathoms. All of the subfamilies occur in the Atlantic as well as 

 in the Indian Ocean, and all of them reach the American side. In all the extra- 

 tropical regions, excepting only the southern shores of Australia and Africa, as 

 well as on the tropical west American coast, the Antedonidse supply almost all, 

 in many places quite all, of the endemic species. 



The subfamily Antedoninse among the macrophreate forms corresponds in 

 many ways to such families as the Comasteridse or Himerometridse among the 

 oligophreate. The four genera included in the subfamily are composed entirely 

 of small littoral species ranging collectively from southern Japan, the Hawaiian 

 Islands, Tonga, Fiji, and southern Australia to the east coast of Africa, and in 

 depth ranging from the shore line down to 78 fathoms in the East Indies, 

 and from 146 to 163 fathoms in the Hawaiian Islands. Ceylon is the only 

 ascertained habitat for Mastigometra ; Gompsometra occurs from southern Japan 

 and the Hawaiian Islands to the southern coast of Australia ; while Iridometra 

 (species related to /. nana) is found throughout the range of the subfamily, 

 except in southern Australia and the Hawaiian Islands ; one third of the species , 

 however, are only known from the Philippines, to which gi'oup of islands 

 the closely allied genus Toxometra is, so far as we know, confined. Outside of 

 the Indian Ocean the genus Antedon, closely allied to Mastigometra, occurs 

 throughout the Mediterranean, and from the Gulf of Guinea to Norway, with a 

 single species on the Brazilian coast. It appears to have reached the Atlantic 

 by passage from the Bay of Bengal " overland " north of India. 



The subfamily Perometrinse belongs to the Intermediate fauna, though to 

 the higher levels in it. It ranges from southern Japan and the Ki Islands to 

 Madagascar in water of from 51 to 140 fathoms in depth, and reappears in the 

 Caribbean Sea where the local representative is the commonest, as well as the 



