A MONOGRAPH OF THE EXISTING CEINOIDS 529 



The other 10 species, included in the subgenus Cenolia, are far less variable in 

 their characters, and in them the range of individual variation is relatively slight. 

 All of them are rather local and several are very local. The only one which occurs in 

 the Malayan Archipelago, where the species of the other group are especiallyabundant, 

 is decidedly rare. 



The largest species (bennetti) of the subgenus Cenolia is rather sharply differen- 

 tiated from the others. It is remarkable for its great size. There may be as many as 

 120 arms which are up to 205 mm. in length. The cirri are large and stout and are 

 peculiar in being composed of up to 35 subequal segments which lack dorsal processes. 

 PI is very long, sometimes reaching nearly 60 mm. The very strongly convex division 

 series of this species, which are also all 4 (3 + 4) and therefore uniformly long, give it a 

 characteristic appearance, whereby it is easily distinguished from the equally large 

 species in other genera. 



A second species (plectrophorum) is to a certain extent intermediate between the 

 preceding and the group of species following, but is unique in having the segments of 

 the proximal and middle pinnules very strongly crested as in Comanthina belli. 



A curious group of 3 large species (pinguis, japonica, and solaster), all closely 

 related and possibly to be regarded as forms of the same species, is found from southern 

 Japan to Hong Kong. Two of these (pinguis and solaster) show a curious correspond- 

 ence to two species of Comantheria (imbricata and intermedia) inhabiting the same 

 region, although the last two seem not to be very closely related to each other. 



On the coasts of southern Australia, Tasmania, and New Zealand there is found 

 a group of 4 species (Irichoptera, tasmaniae, benhami, and novaezealandiae) which are 

 all very closely related to each other. Each of these inhabits a special region where 

 none of the others is found. This contrasts with the conditions occurring in the 

 preceding group, all 3 species of which live together. With this group the small 

 South African species (wahlbergii) shows the closest affinity. 



The last species (samoana) is a rather variable form, which tends to approach the 

 species of the subgenus Comanthus, and indeed is not always easily distinguished from 

 certain forms of C. (C.) parvicirra. 



KEY TO THE 8UBGENEKA OF THE GENUS COMANTHUS 



a 1 . Cirri always present, numerous and evenly distributed about the periphery of the centrodorsal, 

 always well developed and usually stout, with the distal segments markedly shorter than the 

 proximal and laterally compressed, composed of numerous (except in 2 species more than 20) 

 segments; IIBr, IIIBr, and following division series almost invariably 4 (3 + 4); anterior arms 

 never excessively elongate and attenuated (South Africa from Simons Bay to the Tugela 

 River mouth; Ceylon to Tasmania and New Zealand, New Caledonia, Fiji, Tonga, Samoa, the 

 Gilbert, Caroline, and Pelew Islands, southern Japan, and Hong Kong; 0-256 [?548] meters) 



Cenolia, p. 530. 



a 2 . Cirri few, small and weak, with the distal segments only slightly shorter than the proximal and 

 only slightly, if at all, compressed laterally, irregularly distributed about the periphery of 

 the centrodorsal and often confined to the intcrradial angles, sometimes altogether absent; 

 IIBr and IIIBr series usually 4 (3 + 4) and 2 in varying proportions, very rarely all 4 

 anterior arms often excessively elongated and attenuated (Madagascar, Mauritius, the Sey- 

 chelles, and Baluchistan to tropical Australia, New Caledonia, Fiji, Tonga, the Gilbert, 

 Caroline, Pelew, and Bonin Islands, southern Japan, and Amoy, China; 0-110 meters).. 



Comanthus, p. 603. 



