A MONOGRAPH OF THE EXISTING CRINOIDS 159 



center. The five arms are 40 mm. long. The proximal oblong brachials have the dis- 

 tal edges very slightly turned outward and slightly thickened in the center. The 

 arms beyond the proximal discoidal brachials have a smooth dorsal line and appar- 

 ently lack the usual zigzag carination. 



The pinnules of the first pair are 3 mm. long and consist of nine segments, which 

 at first are short, becoming about as long as broad on the third and nearly three times 

 as long as broad distally. The first segment has a high rounded carinate process, 

 which is nearly half as high as the width of the segment. The second has a carinate 

 process, which is not quite so high and which has a straight distal border parallel 

 to the longitudinal axis. The third has a carinate process similar to that of the 

 second, but smaller. The following segments are without carinate processes and 

 therefore appear more slender. The pinnules of the second pair are 4 mm. long and 

 consist of 11 or 12 segments. They are stiffened but are only slightly enlarged. The 

 first segment is twice as broad as the median length, and has the distal angle very 

 slightly produced. The second is slightly broader than the median length, but not 

 quite so broad as the first. The third is half again as long as broad, only about half 

 as broad basally as the first. The fourth is similar to the third but longer, twice as 

 long as broad. The following segments slowly increase in length to about three 

 times as long as the proximal width, the terminal one or two being small as usual. 

 The distal edges of the third and following are produced and spinous, the spines being 

 especially long on the prismatic angles. The pinnules as a whole are rounded pris- 

 matic and taper regularly from the third segment to the tip. The pinnules of the 

 third pair are 3 mm. long and are composed of 11 segments. They resemble those of 

 the second pair, but are more slender with more elongated distal segments. The 

 pinnules of the fourth pair are very slender, weak, and delicate, not stiffened, about 

 3 mm. long, with 10 or 11 segments, which at first are short, becoming half again as 

 long as broad on the third, twice as long as broad on the fourth, and four times as 

 long as broad distally. The third and following have produced and spinous distal 

 ends. The distal pinnules are exceedingly slender, 7 mm. long with 15 or 16 segments 

 of which the third and following are greatly elongated with produced and spinous 

 distal edges. The disk is completely plated. 



Localities.— Sagami Bay, Japan Gat- 34°59' N, long. 139°34' E.); 110 meters 

 [A. H. Clark, 1908, 1912, 1915, 1918;Gislen, 1922] (1,U. S. N.M., 25326 [Owston Coll. 

 No. 6931]). 



No locality; C. Eberstein [A. H. Clark, 1912] (1, H.M.). 



History. — This species was first mentioned, as a nomen nudum, in my paper on 

 new genera of unstalked crinoids, published on April 11, 1908. The occurrence of a 

 single specimen in the Owston collection of Japanese crinoids, which had been pur- 

 chased and presented to the U. S. National Museum by Frank Springer, had enabled 

 me to understand the proximal arm structure and to show that in this species, and 

 also in the related E. indivisus, which I had not then seen, the first two ossicles fol- 

 lowing the radials are homologous with the elements of the IBr series in 10-armed 

 forms. 



Having at hand specimens of the species described by Dr. P. H. Carpenter as 

 Eudiocrinus varians and E. japonicus, as well as of my own recently described E. tuber- 

 culatus, I was able to demonstrate that in these species the IBr series are wholly 



