A MONOGRAPH OF THE EXISTING CRINOIDS 561 



Abnormal specimens. — In the individual from off Hong Kong the right anterior 

 ray is very curiously developed. 



On the right IIBr series (as viewed dorsally) the inner IIIBr series terminates 

 in a doubled axillary — 2 axillaries side by side — which forms an epizygal superposed 

 upon the single hypozygal of the syzygial pair. Each half of this doubled axillary 

 gives off 2 arms so that 4 arms arise from this single division series. Vcntrally the 

 ambulacral groove on reaching this axillarj' divides into 3 parts, 1 of which runs to 

 the left (right as viewed dorsally) and soon divides, supplying 2 arms, while the 

 other 2 run undivided to the 2 remaining arms. 



The left IIBr series arising from this IBr series is undivided. It consists of only 

 9 brachials of which the last bears a single terminal pinnule of large size. The struc- 

 ture tapers regularly from the axillary to the base of the terminal pinnule. The third 

 and fourth brachials are united by syzygy so that this arm stump bears 7 pinnules in 

 all, 6 lateral on alternate sides of the arm and 1 terminal. 



In a specimen from Mortensen's station 10, Gisl&i found a case of distal arm 

 branching. The right posterior ray bears 2 IIBr 4 (3 + 4) series. The inner deriva- 

 tive from each is unbranched. The outer derivative of that to the right carries ex- 

 ternally a IIIBr 4 (3 + 4) series bearing 2 undivided arms. The outer derivative of 

 that to the left forks on the eighth brachial, which is the epizygal of the third syzygial 

 pair, syzygies occurring between brachials 3+4, 5 + 6, and 7 + 8. Doctor Gisl^n in- 

 terprets this as a case of an inner pinnule that has developed into an arm. But he 

 says that here we get a picture of the repetition, as far as possible normal, in more 

 distal parts of the arm of the pro.ximal arm ramification and its distribution of non- 

 muscular articulations. 



In another specimen from Mortensen's station 10, Pi is lacking on an inner arm 

 arising from a IIBr series. 



Another specimen from the same station has 1 of the IIIBr series 2. 



A fourth example from the same station has 1 of the IIBr series 1, 2 of them 2, 

 and the remaining six 4 (3 + 4). 



Remarks. — While in the great majority of cases this species has a very charac- 

 teristic appearance and is readily distinguishable from all other comasterids, it seems 

 to intergrade to a certain extent both with C japonica and with C. solaster. 



It is, perhaps, most easily confused with C. trichoptera which, however, has a 

 discoidal centrodorsal with a broad flat dorsal pole and much more slender cirri. 



Localities. — Eight miles outside Hong Kong Harbor (lat. 22° 12' N., long. 114° 

 15' E.); 25 meters; Captain Suensson, November 16, 1911 [A. H. Clark, 1913; Gisl^n, 

 1927] (1, C. M.). 



Northeast of Swatow, China (lat. 23° 15' N., long. 117° 40' E.); Capt. H. 

 Christiansen, July 26, 1912 (3). 



South of the Goto Islands, Korean Straits (lat. 32° 15' N., long. 128° 20' E.); 

 183 meters; Capt. H. Christiansen, April 17, 1926 (1). 



Between the Goto Islands and Nagasaki (lat. 32° 48' N., long. 129° 37' E.); 73 

 meters; bottom temperature 11.67° C; Capt. H. Christiansen, 8. S. Nordiske, April 

 23, 1912 (5). 



