58 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Hartlaub said that of the other species of the Spinifera group it comes nearest Antedon 

 (Stenometra) quinquecostata Carpenter. Like that species it is characterized by a 

 large number of cirrus segments and a definite arrangement of the cirri. He said that 

 in quinquecostata the centrodorsal is more columnar and the cirri are not arranged in 

 10 columns but in 5 double columns, the 5 double columns being separated by 5 espe- 

 cially high ridges instead of the 10 ridges seen in conifera. But the most important 

 difference is that the arms of quinquecostata have a sharp middorsal keel which in 

 conifera is observable only on the outermost ends of the arms. 



In 1907 I placed Antedon conifera in the synonj^my of A. quinquecostata, of which 

 I said I had seven Japanese specimens. These Japanese specimens represent in reality 

 Stenometra diadema (see page 18). Just why I should have considered conifera a 

 synonym of the very different quinquecostata I cannot now recall. In 1909 I transferred 

 conifera to the genus Stenometra, and later in the same year to Cosmiometra. In 1912 

 I mentioned that I had examined the type specimen of Antedon conifera, but gave no 

 additional information regarding it. Everything we know concerning this species is 

 included in the original description. 



COSMIOMETRA CRASSICIRRA (A. H. Clark) 



PLATE 10, FIGURE 33 



Thalassomdra crassicirra A. H. CLARK, Proc. U. S. Nat. Mus., vol. 34, 1908, p. 214 (in key), p. 225 

 (description; Albatross station 3882; the specimen from station 4107 is the type specimen of 

 Stiremetra decora). 



Cosmiometra crassicirra A. H. CLARK, Proc. Biol. Soe. Washington, vol. 22, 1909, p. 17 (listed); Vid. 

 Medd. Naturhist. Foren. K0benhavn, 1909, p. 186 (allied to C. conifera}; Crinoids of the Indian 

 Ocean, 1912, p. 215 (synonymy; locality); Unstalked crinoids of the Siboga-Kxped., 1918, p. 154 

 (in key; range; references). GISLIJN, Kungl. Fysiograf. Sallsk. Handl., new ser., vol. 45, No. 

 11, 1934, p. 20. A. H. CLARK, Bernice P. Bishop Mus. Bull. 195, 1949, p. 74 (Albatross station 

 3882), p. 93 (station data). 



Diagnostic features. A species with 20 arms in which the elements of the division 

 series and first two brachials are entirely smooth dorsally, and the cirri, which are 

 irregularly arranged in 1, 2, or 3 columns in the several radial areas of the short col- 

 umnar or almost discoidal centrodorsal, are moderately slender, about one-third of the 

 arm length, with 50-54 segments. The arms are 130 mm. long, and the cirri are 45 mm. 

 in length. 



Description. The centrodorsal is broad, short columnar or almost discoidal, with 

 the cirrus sockets arranged in 1, 2, or 3 columns in each radial area. One of the radial 

 areas has 2 marginal columns of cirrus sockets separated by a median space nearly as 

 wide as the cirrus sockets themselves, 3 of the radial areas have 3 columns of cirrus 

 sockets, and the remaining radial area has a single median column of cirrus sockets. 

 There are 1 or 2 cirrus sockets in each column. The broad and flat dorsal pole and the 

 sides of the centrodorsal where there are no cirrus sockets are very rough. 



The cirri are XVII, 50-54, 45 mm. long, moderately slender. The first 4 segments 

 are short, the fifth is about as long as broad, and those following to the fourteenth or 

 sixteenth are about half again as long as broad. The sixteenth is a transition segment; 

 it is but little longer than broad; the distal half or third has a polished surface, the 

 proximal half or two-thirds a dull surface. The next few segments after the transition 

 segment are slightly broader than long, and those succeeding gradually become shorter. 







