A MONOGRAPH OF THE EXISTING CRINOIDS 257 



Localities. Siboga station 129; anchorage off Kawio and Kamboling Islands, 

 Karkaralong group; reef; July 22-23, 1899 [A. H. Clark, 1912, 1918] (2, with penta- 

 crinoids, U.S.N.M., E. 395; Amsterdam Mus.). PL 26, figs. 71, 72. 



Dr. Th. Mortensen's Pacific expedition, 1914-1916; Port Galera, Mindoro, 

 Philippines; February 3, 1914 (1). 



Remarks. The pentacrinoids found on the specimens collected by the Siboga 

 were described in volume 1, part 2, page 513. 



COMISSIA CHADWICKI A. H. Clark 



Plate 65, fig. 185 



Actinometra parvicirra (part) CHADWICK, in Herdman, Report Ceylon Pearl Oyster Fisheries, 

 pt. 2, suppl. rep. 11, 1904, p. 158 (station XLI); plate, figs. 13, 14. 



Comissia, sp. A. H. CLARK, Ann. and Mag. Nat. Hist., ser. 8, vol. 7, 1911, p. 645 (10-armed speci- 

 men of Comanthus parvicirra figured by Chadwick is a species of Comissia; Ceylon, about 

 100 fathoms; Criuoids of the Indian Ocean, 1912, p. 40 (identification of Chadwick's record); 

 p. 78 (synonymy; description, from Chadwick.) 



Comissia chadwicki A. H. CLARK, Proc. Biol. Soc. Washington, vol. 25, 1912, p. 19 (compared with 

 C. parvula; no description); Crinoids of the Indian Ocean, 1912, p. 313 (detailed description 

 of a specimen; identification of Chadwick's record; northeast corner of Ceylon, 28 fathoms); 

 Unstalked Crinoids of the Siboga Exped., 1918, p. 19 (in key; range). 



Diagnostic features. The cirri are XXIV, 11-14, 10 mm. long; the longest cirrus 

 segments are from two to two and one-half times as long as the proximal width. 

 The rather slender arms are about 60 mm. long. The terminal comb on P! has 

 26-28 teeth. 



Description. The centrodorsal 'is thin discoidal with a large flat dorsal pole 

 3.5 mm. in diameter slightly excavated in the center. The cirrus sockets are arranged 

 in a single irregular marginal row. 



The cirri are XXIV, 12-14, 10 mm. long. The fourth and fifth segments are the 

 longest, from two to two and one-half times as long as broad proximally. The sixth 

 and following segments bear minute subterminal dorsal spines. 



The radials are concealed by the centrodorsal. The IBr series are very widely 

 separated laterally. 



The 10 arms are about 60 mm. long and resemble those of C. hispida, but are a 

 trifle more slender. 



The terminal combs on the lower pinnules appear to have 26 or 28 teeth. 



Notes.- The preceding description was drawn up from the specimen from 

 Investigator station 175. According to Chad wick's figure the centrodorsal in his 

 specimen is discoidal, broad and flat, with the cirri arranged in a single somewhat 

 irregular marginal row. The cirri are XVIII, 11, with the fourth segment the 

 longest, not quite three times as long as broad. He describes and figures the disk 

 as covered with minute scalelike plates. 



Localities. Ceylon Pearl Oyster Fisheries station XLI; south of Galle, Ceylon, 

 about 12 miles from land; depth, along the 183 meter line; bottom composed of 

 masses of calcareous branched and ramifying foraminiferal tubes; 1902 [Chadwick, 

 1904; A. H. Clark, 1911, 1912, 1918]. 

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