OE LITTLE-KXOWX COMATUL^. 489 



arches of which are directed upwards, while the two ends slant downwards 

 and outwards. Radials separated from the centrodorsal by a complete 

 circlet of basals. The first six or more brachials bear no pinnules. 



Memarks. Three species of tliis interesting genus are known, 

 two from the Atlantic and one from the Pacific Ocean. One 

 {A. cuhensis) was dredged near Havana in 1868 by theTJ.S. Gulf- 

 stream Expedition, though its singular characters were not then 

 recognized. A second species (A. halanoides) was first obtained 

 by the ' Challenger ' (1873) in the Atlantic, somewhat to the 

 south of Pernambuco. It was subsequently found ofi" the north 

 coast of Cuba by the U.S. steamer ' Blake ' (1877-78), and again 

 at four stations in the Caribbean Sea by the ' Blake' Expedition of 

 1878-79. The remaining species {A. Wyvilli) was dredged by the 

 ' Challenger ' in the neighbourhood of the Eiji Islands. Only one 

 specimen was obtained, which, like the solitary example of A. 

 halanoides from Pernambuco, is very much mutilated. The disk, 

 however, is visible in both, which is not the case with any of the 

 American specimens, though these last have more of the arms 

 preserved. 



From a morphological point of view, Atelecrinus is by far the 

 most interesting of all the free Crinoids, as has been already 

 pointed out in my preliminary ' Blake ' report. The bathymetri- 

 cal range, as at present known, varies from 291 to 450 fathoms; 

 and it has a considerable geographical extension, occurring in the 

 West Atlantic and Mid-Pacific, though not known as yet from 

 any intermediate localities. 



1. Ateleceikus BALAifOiDES, P. H. Carpenter, 1881. 



Antedon cubensis, Pourt. (pars) Bull. Mus. Comp. Zool. vol. v. no. 9, 

 p. 214. 



Atelecrinus halanoides, P. H. Carpenter, Bull. Mus. Comp. Zool. vol. 

 ix. no. 4, p. 16. 



Centrodorsal acorn-shaped, reaching 5 mm. high by nearly 

 3| mm. in diameter. It bears five vertical double rows of cirrus- 

 sockets, the upper ends of which are separated by more or less di- 

 stinct interradial ridges. Pour to six sockets in each row, the 

 dorsal pole, though rough, being free from functional sockets. 

 The ends of their horseshoe-shaped rims slant downwards and 

 outwards, but are much more prominent in some individuals than 

 in others. 



The cirri have three or four quite short, almost triangular basal 

 joints. The next joint is twice as long as wide, and its successors 



