20 ECHINODEBMA OF THE INDIAN MuSEUM, PART VII. 



4. DISTKIBUTION OF THE EAST INDIAN CRINOIDS 

 BY FAMILIES. 



Co^nasterida'. 



Species of the family Comasteridse occur throughout the East Indian region, 

 giving to its fauna one of its most distinctive characteristics. The great majority 

 of these specie.s are Httoral and sublittoral , occurring from the low tide mark down 

 to a depth of usually less than 50 fathoms. Small species of the family are found 

 everywhere, but the large species with very numerous arms are almost all confined 

 to the area lying between the northern coast of Australia, the Nicobar and 

 Andaman Islands, Luzon and New Guinea, a very few, more hardy or more 

 enterprising than the rest, extending to Ceylon and the Maldive Islands on the 

 west, Fiji on the east, and to Japan on the north. In this district, also, are 

 found the smallest species, showing that the extremes within a single family, as 

 we have seen the extremes within the whole class, do not wander far from the 

 area offering the optimum conditions for existence, only the more generalized 

 medium-sized types being sufficiently adaptable to enable them to intrude into 

 new territory. 



Of the three subfamilies, the Comasterinae, which contains the largest and 

 most multibrachiate, as well as the smallest species, is the most restricted, both 

 geographically and bathymetrically. This subfamily occurs from East Africa to 

 Tasmania and South Australia, Samoa, Tonga, Fiji and Japan — even a single 

 one of its species covering most of this territory — but of its 30 species 18, or 

 nearl}' two- thirds, are confined to the centre of the East Indian region. Only 

 three of the species are known to occur deeper than 50 fathoms, and these are 

 all from southern Japan, and all species peculiar to that region. 



The subfamily Comactiniinae is especially characteristic of Australia, and five 

 of the eight species are confined to the shores of that continent, or at most 

 occurring in southern New Guinea. One species ranges north to Singapore and 

 the Philippine Islands, and another even reaches Hong Kong, while a curious 

 form is only known from the Andaman Islands. The single species of the genus 

 Cominia occurs in the Korean Straits. Though mostly littoral and sublittoral, 

 one species [Cominia decameros) extends downward to 170 fatlioms. Curiously 

 enough, though so restricted in geographical range in the East Indies, this sub- 

 family reappears in the Caribbean Sea ranging on the American Atlantic coast 

 from Brazil to Carolina. 



The species of tlie subfamily Capillasterinse are somewhat more general in 

 their distribution than are those of the other subfamilies. Representatives of all 

 the three genera occur from south-eastern Africa to the South Sea Islands and 

 Japan, and are found from the shore line down to 60 [Gom.issia) , 140 (Coinatella), 

 and 160 (Gapillaster) fathoms. Each of these genera has a close ally in the 

 tropical Atlantic (Leptonemaster , N eocomatella , Nema&ter). 



