332 THE VOYAGE OF H.M.S. CHALLENGER. 



next syzygy is from the eighth to the thirtieth brachial, after which there is an interval of 

 five to eleven joints between successive syzygies in the free arms. These consist of from 

 ninety to one hundred slightly overlapping joints, nearly oblong in shape in the lower 

 parts, but gradually becoming squarer, and finally elongated. 



The first pinnule is on the first distichal, if it be united to the second by muscles. 

 In other cases the second distichal bears the first pinnule ; and the same is the case in 

 the free arms. The lowest pinnules consist of about a dozen flattened joints, all of 

 which except the first are longer than broad. They have sharp dorsal edges, and are 

 much flattened laterally, especially those near the base of the pinnule, the terminal 

 ones being more slender, so that the pinnule tapers considerably. Farther out on the 

 arm the joints become more equal, the three lowest being the only ones that are much 

 flattened, but the pinnules do not increase greatly in length. 



The disk bears numerous plates of variable size, rather closely set, but not forming 

 a perfectly continuous pavement ; and several of them support small blunt spinelets. 

 The ambulacra of the disk and arm-bases are protected by somewhat narrow and spine- 

 like plates irregularly disposed. Arm-groove moderately wide and continuously plated. 

 Pinnule-ambulacra variable, sometimes having moderately distinct side plates and some- 

 times hardly any trace of them. 



Colour when fresh, white, purple, or yellow (Sigsbee), bleaching nearly white in spirit. 



Localities. — 'Abundant in the Gulf Stream and in the Caribbean Sea, but not known 

 elsewhere. A few specimens have been obtained by the collectors for Sir Eawson Eawson 

 and Mr. Damon ; also by W. Stimpson ofl" Cuba, and by Captain E. Cole of the telegraph 

 steamer " Investigator " at the following localities — south side of Porto Rico, 667 fathoms ; 

 ofi^ Saba Island, 320 fathoms (with Pentacrinus asterius) ; between Saba and Eustatius 

 Islands, 531 fathoms (with. Pentacrinus miilleri). But great numbers have been dredged by 

 the surveying ships of the U.S. Coast Survey, as recorded in the following list : — 



S.S. "Corwin," 1867. 1-6 miles from Chorrera, Cuba, 270 fathoms. 



S.S. "Bibb," 1869. Off Double-headed Shot Keys ; 315 and 471 (?) fathoms. 



S.S. " Blake," Cruise of 1877-78. No. 21, off Bahia Honda; lat. 23° 2' N., long. 83° 13' W. ; 287 fathoms. Off 



Havana (Sigsbee); 150 to 200 fathoms. No. 56, off Havana; lat. 22° 9' 15" N., long. 82° 21' W.; 



175 fathoms. No. 57, off Havana; lat. 22° 9' K, long. 82° 21' W.; 177 fathoms. 

 Cruise of 1878-79. No. 100, off Morro Light; 250 to 400 fathoms. No. 101, off Morro Light; 175 to 250 



fathoms. Nos. 155 and 156, off Montserrat; 88 fathoms; bottom temperature, 69° F. No. 157, off 



Montserrat ; 120 fathoms; bottom temperature, 69° F. No. 233, off St. Vincent; 174 fathoms; rooky 



bottom; bottom temperature, 49J°F. No. 269, off St. Vincent; 124 fathoms; bottom temperature, 5 7 J" F. 



No. 296, off Barbados; 84 fathoms; bottom temperature, 61^° F. No. 298, off Barbados ; 120 fathoms; 



bottom temperature, 61° F. 

 Cruise of 1879-80 (Bartlett). Off Santiago de Cuba. Off Kingston (Jamaica); 100 fathoms. 



Captain Sigsbee ^ describes the specimens dredged by him in the following terms : — 

 " Some of them came up on the tangles, some on the dredge. They were as brittle as 



1 Bull. Mus. Comp. Zobl, vol. v.. No. 6, p. 60. 



