484 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Another species (rotula) possesses only rudimentary cirri, but only 40 arms. 

 This, however, is not closely related to the preceding species, but to another group 

 of forms (including weberi, perplexum, and intennedia) in which the cirri are well 

 developed and the arms are always about 40 in number. These species {rotula, 

 weberi, 'perplexum, and intermedia) are more likely to be confused with Comanthus 

 timorensis than with any other species of the genus Comantheria. But the curious 

 wheel-like appearance resulting from the possession of 40 arms and the short IIIBr 

 series distinguish them at once from any species of Comanthus. 



In another group of species (including grandicalyx and imbricata) the cirri are 

 large and robust and in length are equal to about one-third of the arm length. The 

 number of arms varies between 30 and 68. The general aspect of these species, due 

 to the large ceutrodorsal and long and robust cirri, is cjuite different from that of 

 any of the other species. In a general way they resemble the species of Comanthus 

 having large stout cirri, especially C. japonica and C. pinguis; but their appearance 

 is quite characteristic and a glance at the IIIBr series distinguishes them at once. 



The remaining two species, which do not in any way resemble each other, are 

 curious in having terminal combs as far as the thirty-first brachial (delicata), or even 

 occurring at intervals on the distal pinnules. In taviana the cirri are small, with 

 relatively few segments, while in delicata these organs are large and stout, with more 

 numerous segments. The last named has a general appearance quite different from 

 that of any other comasterid. 



KEY TO THE SPECIE3 IN THE GENUS COMANTHERIA 



a'. Centrodorsal greatly reduced; cirri absent or, if present, rudimentary. 

 6'. More than 45 arms. 



c'. IVBr series 2; succeeding division series 2 except the outermost, which are 4 (3 + 4); 85-160 



arms (Philippine to the Kei Islands; 0-51 meters) polycnemis, p. 485. 



c^ IVBr series 4 (3 + 4). 



d'. VBr series 2; VIBr series, when present, 4 (3 + 4); 80-160 arms (Philippines to Port 

 Molle, Queensland, and the Abrolhos Islands, Western Australia; 0-51 meters) 



alternans, p. 488. 



#. VBr and following series 4 (3 + 4); 48-170 (usually 70-100) arms (Java and northern 



Australia to the Philippines and Formosa [Taiwan]; 0-91 meters)., briareus, p. 492. 



¥. Arms 40 in number (Timor, Aru Islands, northwestern Australia, and the Philippines; 0-27 



[?54] meters) rotula, p. 503. 



a'. Centrodorsal well developed, usually large and thick, bearing numerous long and weU-developed 



cirri. 



6'. Cirri of moderate size, in length equal to between one-eighth and one-fifth of the arm length. 



c'. Cirri with 20-28 (usually 24-26) segments, of which the longest are about one-third again 



as long as broad; 31-48 arms (Sagami Bay, Japan, to Amoy, China; down to about 



150 meters) intermedia, p. 508. 



c'. Not more than 20 (16-20) cirrus segments, of which the distal bear dorsally a tubercle in 

 the proximal portion in addition to the distal tubercle or transverse ridge, so that the dorsal 

 profile of the distal cirrus segments is bidentate. 

 d'. No combs on the middle and distal pinnules. 



e'. Cirri larger and more numerous, XXXII, 19-20, about 20 mm. long; 40 arms (Lesser 



Sunda Islands; 69 meters) weberi, p. 505. 



e2. Cirri smaller and fewer, apparently XV-XX, 16-19, about 13 mm. long; 44 arms (off 



BaUina, New South Wales; 49-51 meters) perplexum, p. 506. 



d^. Combs occur on most of the genital pinnules, as well as on many of the distal pinnules; 

 36 arms (Jolo Archipelago; 89 meters) taviana, p. 510. 



