28 ECHINODERMA OF THE INDIAN MUSEU.M, TART VII. 



Antarctic Ocean, and nortli, in the Atlantic, to the Canaries ; but none of the 

 genera are well understood. Oalaniocrinus is found in the Galapagos Islands and 

 off the west coast of Central America in from 392 to 782 fathoms; Ptilocrinus is 

 known from the Queen Charlotte Islands in 1,588 fathoms, from the extreme south 

 of the Pacific in 240 fathoms, and from the extreme south of the Atlantic ; Tha- 

 Jassocrinus occurs in the Philippines in 1,262 fathoms; and Hyocrinus in the Cro- 

 zet Islands, south of Africa, in 1,000 fathoms, dephyrocrinus is from the Canary 

 Islands. 



Phrynocrinid<r . 



The family Fhrynocrinidw is as yet only known from the single specimen of 

 the type species of Phrynocrinus which I dredged off southern Japan in 649 

 fathoms. 



Bourg u eticrinid(c . 



The genus Rhizocrinus of the family Bourgueticrimdct was first known to 

 occur in the recent seas through having been discovered, together with a human 

 skeleton, in a recent breccia at Guadeloupe in the Lesser Antilles, a few years later 

 being found off Norway, and almost at the same time off Barbados and off Portugal. 

 At the present time it is known from Norway and Cape Cod to the Argentine, and 

 from Somaliland to the Philippine Islands, in the East Indian region extending 

 from 56 to 1,025 fathoms. Bathycrinus, the other recent genus of the family, 

 occurs everywhere in deep water, entering the deep cold stagnant basins, ranging in 

 the Indian and Pacific Oceans from 650 down to 2,320 fathoms.' 



5. THE IMPORTANCE OF CRINOIDS. 



Economically the crinoids serve no useful purpose, at least up to now they 

 have been put to none. Owing to their ordinarily fixed mode of life, however, 

 they can be used as an accurate index to the plankton content of the surrounding 

 water, whereby an accurate idea may be had, at a small expenditure of time, 

 labour, and money, of its ability to support other marine life such as marketable 

 fish, coral, sponges, or pearl oysters. A careful study of the crinoid species, their 

 ecology, their food (as evidenced by their stomach contents), and their habits 

 should be undertaken so that the information oifered by them, undoubtedly of 

 considerable value, may be readily appreciated. So far absolutely nothing has 

 been done in this direction. 



The chief interest in the crinoids lies in their relation to the study of fossils. 



J HolopidcB. 



The family Holopida' has been created to contain tlie curious genus Holopus, an extraordinary 

 massive .short-armed crinoid with an asymmetrical crown, seasile, or mounted upon a short thick 

 unjointed stem. It occurs, so far as is now Unown, only in the West Indies, among the Lesser An- 

 tilles, in water of from 5 to 100 fathoms in depth. Two species have been described, H. rangii from 

 Martinique, with eight arms, and H. rawsoni fiom Barbados, with ten: both, however, represent the 

 same form. Carpenter unfortunately overlooked the latter in the preparation of the " Challenger " 

 report. 



This genus is especially to be looked for in the East Indies. 



