530 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Subgenus Cenolia A. H. Clark 

 Benneltia A. H. Clark, Videusk. Medd. fra den naturhist. Forening i K0benhavn, 1909, p. 142 

 (type Aleclo bennetti J. Muller, 1841; diagnosis); Proc. U. S. Nat. Mus., vol. 40, 1911, p. 13 

 (common to South Africa and Ceylon, but not found in the Arabian Sea); Mem. Australian 

 Mus., vol. 4, 1911, p. 754 (original reference; characters; range); Crinoids of the Indian Ocean, 

 1912, p. 10 (greatly developed in Japan); p. 11 (occurs both east and west of Ceylon); p. 12 

 (represented in the southeast African region); p. 93 (synonymy ; = GoZd/"Mssia Norman, pre- 

 occupied; type). 

 Cenolia A. H. Clark, Proc. Biol. Soc. Washington, vol. 29, 1916, p. 48 (subgenus; no diagnosis; used 

 in the combination Covianthus [Cenolia] trichoptera) ; Unstalked Crinoids of the Siboga Exped., 

 1918, p. 34 (in key; range); p. 48 (subgenus of Comanlhus; in key). 



Diagnosis.— A subgenus of Comanthus including those species in which the IIBr 

 series are almost invariably 4 (3 + 4), and the cirri are always present and numerous, 

 usually stout, laterally compressed distally, and evenly distributed about the periph- 

 ery of the ccntrodorsal. 



Geographical range. — From southern Japan, Oceania, and Australia to Ceylon and 

 southern Africa. This subgenus alone is represented in New Zealand, Tasmania, 

 southern Australia, and southern Africa, and is the characteristic comasterid type in 

 southern Japan. 



Bathymetrical range. — From the shore line down to 256 meters. This subgenus 

 occurs for a considerable depth beyond the lowest limit of the other subgenus, 

 Comanthus. 



KET TO THE SPEQES rU THE SUBGENUS CENOUA 



a'. More than 60 (usually more than 70) arms; cirri with the distal segments only slightly shorter 

 than the proximal, dorsally more or less swollen, but entirely without dorsal processes; 

 ccntrodorsal very large, hemispherical, with a deeply concave dorsal pole; cirri large, stout, 

 well developed, and numerous, with 20-35 (usually 25-30) segments; size large, the arms 

 130-205 mm. long (Andaman Islands to northern Australia, the Loyalty, Pelew, and Marshall 



Islands, the Philippines, and Macclesfield Bank; 0-50 [?04] meters) bennetti, p. 531. 



o'. Less than 60 arms; cirri with the distal segments much shorter than the proximal and always 



with a more or less developed dorsal process in the form of a keel, tubercle, or carinate spine, 



or sometimes a distal serrate transverse ridge. 



6'. Cirri very long, stout, and numerous, the longest composed of more than 32 segments; cen- 



trodorsal large, more or less hemispherical, with a relatively small concave dorsal pole; 



usually about 40 arms; size large, the arms 100-200 (commonly 150-200) mm. in length. 



c". Proximal and middle pinnules with the segments in the basal portion produced dorsally 



into conspicuous dorsal processes which on the lower segments may be as high as the 



width of the segments themselves (southeastern Australia and Bass Strait; 183-548 



meters) plectrophorum, p. 550. 



c2. No conspicuous dorsal processes on the basal segments of the proximal and middle pinnules. 



d'. Division series very broad, so that only narrow strips of perisonie, or none at all, are 



visible between them, and much flattened dorsally; axillaries with the anterior angle 



acute (southern Japan to Hong Kong; 25-188 [?28S] meters) pinguis, p. 553. 



d^. Division series narrow and strongly convex dorsally, so that large areas of perisome are 

 visible between them; axillaries with the anterior angle acute (southern Japan; 0-256 



meters) japonica, p. 564. 



b'-. Cirri shorter and more slender, with fewer than 30 (usually fewer than 25) segments; centro- 

 dorsal discoidal with a broad flat dorsal pole; seldom more than 35 arms; size smaller, 

 c'. Cirri mostly more or less undeveloped and very variable in size, composed of a very variable 

 number of segments, though always with fewer than 30 and usually with fewer than 

 25; division series very broad and flattened dorsally and in cl5se lateral contact, so that 

 no perisome is visible between them (southern Japan and southward to Formosa [Taiwan]; 

 0-197 meters) solaster, p. 576. 



