A MONOGRAPH OF THE EXISTING CRINOIDS 103 



diminish in length to the small terminal segment. The second-fourth segments are 

 slightly constricted centrally. P 2 is 4 mm. long with 9 segments, similar to Pj but 

 very slightly stouter and with slightly shorter segments. P 3 is from 2.5 to 3.0 mm. 

 long with 8 segments, and is more slender and less stiffened than the pinnules pre- 

 ceding. P! is 2 mm. long, small, slender, and weak, with 8 or 9 segments. The next 

 two pinnules are similar to P 4 , and those succeeding gradually become elongated, the 

 distal pinnules being from 4.5 to 5.0 mm. in length with 13 segments of which the 

 majority are from 2 to 3 tunes as long as broad and very slender. 



The color in alcohol is white. 



Notes. The specimens from Willebrord Snellius station 60* are small and imma- 

 ture. One is light violet with the ends of the segments narrowly yellow, and the other 

 is white with groups of narrow transverse lines of deep violet, one to a segment. 



Localities. Siboga station 305; mid-channel in Solor Strait, off Kampong 

 Menanga; 113 meters; stony bottom; February _8l900 [A. H. Clark, 1912, 1918; 

 Gislen, 1919] (1, Amsterdam Mus.). 



Willebrord Snellius station 60*; lat. 6 58' 00" N., long. 121 52' 30" E.; 72-80 

 meters; September 5, 1929 [A. H. Clark, 1936] (2, L. M.). 



History. This species was originally described hi 1912 under the name Oligometra 

 marginata from a single specimen collected by the Siboga at station 305; but hi the 

 detailed report upon the Siboga collection published hi 1918 Oligometra marginata was 

 placed in the synonymy of Oligometrides adeonae, of which it was supposed to be a 

 young individual. The discovery of two additional specimens by the Willebrord 

 Snellius again brought up the question of the status of this form, and further study 

 showed, in the light of information acquired subsequent to the publication of the 

 Siboga report, that whatever its relations may be with the other species of the recently 

 recognized genus Iconometra, marginata has nothing to do with Oligometrides adeonae. 



ICONOMETRA INTERMEDIA (A. H. Clark) 



Oligometra intermedia A. H. CLARK, Rec. Indian Mus., vol. 7, pt. 3, No. 26, 1912, p. 269 (description; 

 Andaman Islands) ; Unstalked crinoids of the Siboga-Exped., 1918, p. 125, footnote ( = Prometra 

 intermedia). G:SLN, Kungl. Svenska Vet. Handl., vol. 59, No. 4, 1919, p. 33 (discussion). 

 Prometra intermedia A. H. CLARK, Unstalked crinoids of the Siboga-Exped., 1918, p. 125 (in key; 

 range) . 



Diagnostic features. The cirri are 2.5 mm. longwith 10 or 1 1 segments of which the 

 sixth and following are about as long as broad and the distal bear paired transversely 

 elongate dorsal spines; PI is the longest and stiff est pinnule on the arm, 2.5 mm. long 

 with 8 segments; P 2 is 2 mm. long with 8 segments and resembles PI; P 3 is only half as 

 long as P 2 , though it also has 8 segments; the arms are about 18 mm. long. 



Description. The centrodorsal is small, discoidal, with the dorsal pole 0.8 mm. 

 in diameter, flat and papillose. 



The cirri are IX, 10-11, 2.5 mm. long, veiy short, very stout, and strongly 

 curved. The earlier segments are broader than long, but the sixth and following are 

 about as long as broad. The second segment has the distal dorsal edge produced and 

 finely spinous, this production becoming on the fourth a median transverse ridge with 

 prominent lateral angles which project slightly beyond the lateral profile of the segment 

 and encroach slightly on the lateral surface. On the distal segments this transverse 

 ridge becomes narrower and partially resolves itself into paired transversely elongate 



