A MONOGRAPH OF THE EXISTING CRINOIDS 287 



The integument over the gonads contains irregular phites and spicules of various 

 sizes which are not in contact with each other. 



The tentacles contain numerous spicules in the proximal portion. 



Two to four large oval or circular perisomic iaterradials, which are usually not 

 quite contiguous, are found in each interradial angle. 



The disk, except for the perisomic interradials, is naked. The mouth is central 

 and very large. The anal tube is small and marginal. 



Sacculi are present on the pinnules, though they are not numerous. 



Localities.— Albatross station 2670; off Brunswick, Ga. (lat. 31° 20' 00" N., 

 long. 79° 22' 00" W.); 512 meters; temperature 6.95° C; gray sand and dead coral; 

 May 5, 1886 [A. H. Clark, 1909] (13, U.S.N. M., 14706, 25460, 34629, 34631). 



Albatross station 2671; off Brunswick, Ga. (lat. 31° 20' 00" N., long. 79° 22' 

 00" W.); 512 meters; gray sand and dead coral; May 5, 1886 (18, U.S.N.M., 14699, 

 15975, 34626). PI. 30, figs. 89-92. 



Remarks. — This species has not been found since the original material was 



obtained. 



Genus MICROCOMATULA A. H. Clark 



Microcomatula A. H. Clark, Amer. Journ. Sci., ser. 4, vol. 32, 1911, p. 129 (nomen nudum; charac- 

 teristic of the West Indian fauna; significance; appears to have been derived from Comissia); 

 Unstallied Crinoids of the Siboga Exped., 1918, p. 4 (in key); Univ. Iowa, Studies in Nat. 

 Hist., vol. 9, No. 5, 1921, p. 12 (confined to the West Indies); p. 16 (in key); The Danish 

 I ngolf -Exped., vol. 4, No. 5, Ciinoidea, 1923, p. 39 (range); p. 51 (in key). 



Diagnosis. — A genus of Capillasterinae, including small species with 10 arms only 

 ami a central mouth; all the pinnules are present; the cirri are excessively slender 

 and delicate with enormously elongated segments and swollen articulations; the first 

 cirrus segment is longer than ])road, and the penultimate, which is much shorter than 

 those preceding, is t\\"ice as long as broad; the terminal comb on the oral pinnules 

 consists of 3 very long lance-head-like teeth. 



Geographical range. — Onh^ known from the Virgin Islands. 



Bathymetrical range. — Dredged between 91 and 183 meters. 



Eemarlcs. — The single species of Microcomatula, first described below, is the small- 

 est of all the living crinoids, although it is only slightly smaller than the smallest 

 species in the Antedonidae. It is interesting that, with so many giant forms which 

 in bulk if not in arm length exceed all other comatulids, the family Comasteridae 

 should include the very smallest living species. The next smallest species, together 

 with the species with the greatest length of arm, belong to the family Antedonidae. 



MICROCOMATULA MORTENSENI, sp. nOT. 



Description. — The centrodorsal is low hemispherical, almost entirelj' covered with 

 cirrus sockets and with a very small bare dorsal pole; the cirrus sockets stand up 

 some distance from the general surface. 



The cirri are about XL, 8-9, the peripheral 4.5 mm. long, the apical about half 

 that length, excessively slender and threadlike, with abruptly and conspicuously 

 swollen articulations. The first segment is longer than broad, the second is about 

 four times as long as broad or longer, and the following are greatly elongated, 

 the third and fourth being the longest. Beyond the fourth the length diminishes 



