A MONOGRAPH OF THE EXISTING CRINOIDS 403 



History. This species was originally described in 1908 from a single specimen 

 in the Zoological Museum at Copenhagen. In 1922 Dr. Torsten Gisl6n recorded a 

 specimen which he tentatively referred to this species which had been collected by 

 Dr. Sixten Bock in Sagami Bay in 1914. 



COMATULIDES AUSTRALIS (A. H. Clark) 



Plate 45, Figures 138, 139 



Cominia australis A. H. CLARK, Proc. Biol. Soc. Washington, vol. 25, 1912, p. 21 (description; 

 Siboga station 297). 



Comatulides australis A. H. CLARK, Unstalked Crinoids of the Siboga Exped., 1918, p. IX (relation- 

 ship with C. decameros); p. 32 (in key; range; references; detailed description; stations 267, 297); 

 p. 275 (listed); pi. 15, figs. 21, 22. 



Diagnostic features. This species differs from C. decameros in having fewer 

 (XXIV) cirri which are composed of fewer (12-13) segments and are very slightly 

 stouter and less strongly compressed distally; the synarthrial and articular tubercles 

 are not so prominent as in C. decameros, but the rugged character of the arm bases is 

 indicated, and might become prominent in larger examples. 



Description. The centrodorsal is thin discoidal, with the bare dorsal pole flat, 

 2 mm. in diameter. The cirrus sockets are arranged in three closely crowded roughly 

 alternating marginal and submarginal rows. 



The cirri are XXIV, 12-13, from 13 to 15 mm. long. The first segment is short, 

 the second is nearly or quite twice as broad as long, the third is twice as long as the 

 diameter of the ends, the fourth-sixth are three times as long as the median diameter, 

 and the following decrease in length so that the antepenultimate is about one-third 

 again as long as broad. The opposing spine is represented by a slight subterminal 

 tubercle. The terminal claw is longer than the penultimate segment, rather stout, 

 and moderately curved. The longer proximal cirrus segments have slightly swollen 

 distal ends, this character gradually disappearing as the segments become shorter. 

 The eighth or ninth segment becomes lighter in color distally, and is a slightly marked 

 transition segment, though the preceding segments are smooth, like the following. 

 The last 4 or 5 segments before the penultimate have their distal dorsal margin very 

 slightly thickened. The cirri are moderately compressed laterally, this compression 

 increasing slowly and uniformly from the base to the short outer segments. 



The ends of the basal rays are very prominent as rounded tubercles hi the inter- 

 radial angles. The subradial clefts are very narrow and very deep. 



The radials are concealed in the median line, being visible only at the side of 

 and above the ends of the basal rays; their distal angles are separated by a prominent 

 V-shaped gap. The IBr, are very short, slightly trapezoidal, narrower distally than 

 basally, three times as broad as long, very widely separated laterally, the sides of 

 adjacent IBr, making more than a right angle with each other. The IBr 2 (axil- 

 laries) are very broadly pentagonal, almost triangular, about twice as broad as long, 

 their lateral edges about half as long as those of the IBr b with which they make 

 slightly more than a right angle. 



Arms 10, probably about 90 mm. long, resembling those of C. decameros, but not 

 so rugged and with only mere traces of synarthrial and articular tubercles. The 



