534 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Jaluit; Ekalin, St. Matthias I.; descriptions of the specimens); Proc. U. S. Nat. Mus., vol. 43, 

 1912, p. 391 (South Seas; St. Mathias I.); Crinoids of the Indian Ocean, 1912, pp. 3, 31, 36, 

 37, 38, 39 (identity of previous records) ; p. 18 (centrodorsal always remains essentially as in 

 the young); p. 93 (synonymy; Table I.; description; summary of previous records; remarks on 

 the synonymy) ; Proc. Biol. Soc. Washington, vol. 26, 1913, p. 180 (variety occurring at St. 

 Mathias I. compared with C. japonica); Smiths. Miscell. Coll., vol. 61, No. 15, 1913, p. 15 

 (published references to specimens in the British Museum; Maccelsfield Bank, 13 fathoms; 

 Loyalty Is.; New Britain; Lelti I.; characters of the specimens); Internat. Revue d. gesamt. 

 Hydrobiol. u. Hydrogr., 1915, p. 223 and following (detailed account of the distribution in 

 Australia). H. L. CLARK, Biol. Results Fishing Exper. F. I. S. Endeavour, 1909-1914, vol. 

 4, pt. 1, 1916, p. 16 (comparison with C. plectrophorum) . HARTMEYER, Mitt. zool. Mus. Berlin, 

 vol. 8, Heft 2, 1916, p. 234 (St. Mathias I., No. 5939). A. H. CLARK, Unstalked Crinoids of 

 the Siboga Exped., 1918, p. 48 (in key; range); pp. 273-275 (listed); pi. 16, fig. 25; Smiths. 

 Miscell. Coll., vol. 72, No. 7, 1921, pi. 1, fig. 17 (arm structure). H. L. CLARK, The Echinoderm 

 Fauna of Torres Strait, 1921, p. 192 and following (range). 



Comanlhus (Benneltia) bennetli A. H. CLAHK, Memoirs Australian Mus., vol. 4, pt. 15, 1911, p. 754 

 (annotated synonymy; characters; Australian records; range; includes Actinometra robustipinna 

 of Koehler, but not of Carpenter, which last is a species of Himerometra) . 



Comanthus crassicirra A. H. CLARK, Proc. Biol. Soc. Washington, vol. 25, 1912, p. 23 (description; 

 Siboga station 133); vol. 26, 1913, p. 180 (compared with C. japonica). 



Comanthus (Cenolia) bennetti A. H. CLARK, Unstalked Crinoids of the Siboga Exped., 1918, p. 50 

 (synonymy; notes; stations 133, 240, 299). 



Diagnostic features. The centrodorsal is large, flattened hemispherical, with the 

 dorsal pole concave. The cirri are numerous, large and stout, with 23-35 (most 

 commonly 25-30) segments, of which the distal are only slightly shorter than the 

 earlier and, though swollen dorsally, are without dorsal processes or a dorsal carina- 

 tion. The arms are 48-120, usually 80 or more, in number, and are up to 205 mm. 

 in length. 



The general appearance of this species, with its long and strongly convex division 

 series, large centrodorsal, and numerous stout cirri lacking dorsal processes, is very 

 characteristic and unlike that of any other comatulid. 



Description. The centrodorsal is large, flattened hemispherical, 12 mm. in 

 diameter, with the concave dorsal pole 6 or 7 mm. across. The cirrus sockets are 

 large and very closely crowded, arranged in usually 4 alternating rows. 



The cirri are XL-LX (rarely as few as XX or XXV), 23-35 (most commonly 

 25-30), large and stout, from 30 to 40 mm. in length. The first segment is very 

 short and the following gradually increase in length to the sixth, which, with the 

 remainder, is slightly broader than long, the distal segments being only very slightly 

 shorter than those nearer the base. The cirrus segments are all perfectly smooth 

 and rounded dorsally, with no trace of spines or carination. The dorsal profile of 

 the segments in the distal half is more convex than of those in the proximal half. The 

 opposing spine is represented by a minute blunt median tubercle which arises in an 

 obtuse angle from the entire dorsal surface of the penultimate segment. The terminal 

 claw is usually half again as long as the penultimate segment and is stout basally, 

 becoming slender in the distal half, and moderately curved. 



The ends of the basal rays are visible in the interradial angles of the calyx; in 

 cross section or in end view they are more or less like a trefoil in outline. 



The radials are concealed by the centrodorsal in the median line, but their 

 anterolateral angles rise abruptly in the interradial angles, forming over the ends 



