86 BULLETIN 82, UNITED STATES NATIONAL MUSEXJM 



series of 3 (2 + 3) the first element, following the preceding axillary, bears a pinnule; 

 in species with 10 arms, and in species with more than 10 arms in which all the divi- 

 sion series are 2, the first pinnule is on the second brachial; the genital pinnules are 

 not especially stout, and their component segments are not especially short. 



Geographical range. — From southwestern Japan, the Bonin and Caroline Islands, 

 Samoa, Fiji, Tonga, New Caledonia, and Tasmania westward to the Red Sea, the 

 Amirante Islands, the Seychelles, Madagascar, and Mauritius; from Brittany to the 

 Canary Islands; from Cape Lookout, N. C, and southern and western Florida and 

 the Bahamas southward throughout the Caribbean Sea and Gulf of Mexico to Bahia, 

 Brazil. 



Bathymetrical range. — From the low-tide mark down to 1,710 meters. The 

 relative frequency of the included genera at different depths is as follows: 



0-100 meters 8 



100-200 meters 9 



200-300 meters 7 



300-400 meters 4 



400-600 meters 3 



600-1,000 meters 2 



Over 1,000 meters 1 



Remarks. — In contrast to the subfamilies Comactiniinae and Comasterinae, the 

 subfamily Capillasterinae is a rather heterogeneous group. Of the 11 included 

 genera, 5 contain invariably 10-armed species, one contains a single species of which 

 most of the individuals have 10 arms, and 5 include species with always more than 

 10 arms, the number running up to about 100 in exceptional specimens of Capillaster 

 sentosa. In several of the midtibrachiate species the arm number varies between 

 unusually wide extremes; for instance, in Comatella nigra there may be anywhere 

 from 29 to 80 or more arms. 



The arm division in Capillaster and Nemaster is of a curious type not found 

 elsewhere in the comatulids, though occurring in the pentacrinites. The arm division 

 of Comatella, Neocomatella, and Palaeocomatella resembles that found in the multi- 

 brachiate species included in the subfamily Comactiniinae. 



It was because of the close correspondence in the structm-e of the cirri that I 

 originally placed Capillaster, Nemaster, Comatella, Neocomatella, and Palaeocomatella 

 in the same subfamily, their cirri being very different from those characteristic of 

 the species of the Comactiniinae. The correctness of this disposition was later 

 confirmed by the discovery of curious individuals of species of Capillaster and Coma- 

 tella which had some of their division series of the type characteristic of the other 

 genus. 



In the genera Capillaster and Nemaster certain individuals of the included species 

 have the division series very highly irregular, and not infrequently consisting of a 

 single axillary ossicle only. This is seen particulariy in Capillaster mariae, C. multi- 

 radiata, and Nemaster iowensis. Such irregularity in the division series does not 

 occur in any other group of comatulids. While irregularities in the division series 

 are very frequent in most of the species of Comasterinae, they here consist simply 

 of the replacement of a division series of 4 (3 + 4) by one of 2, or the reverse. 



In the Capillasterinae the cirri are always numerous and well developed, except- 

 ing only in Capillaster macrobrachius , in which species they are absent. The number 

 of cirrus segments varies from 8 or 9 in Microcomatula to occasionaUy 40 or more 



