A MONOGRAPH OF THE EXISTING CRINOIDS 507 



without synarthrial tubercles. The distal margins of the ossicles are distinct and 

 slightly flaring, especially on the IIBrj. The entire IIBr series is only 5 mm. long, 

 but is neariy 4 mm. broad. The IIIBr series are 2, except on a single IIBr series, 

 where one branch bears a IIIBr 4 (3 + 4) series and the other is imdivided. There 

 are 4 IVBr series present, all of which are 4 (3 + 4). 



The 44 arms are about 100 nun. long, and consist of approxunately 100 brachials 

 beyond the last axillary. The brachials are quadrilateral, but except near the tip 

 of the arm the side bearing the pinnule is much longer than the one opposite. The 

 distal edges of the brachials are flaring, thickened, and minutely rough, but not 

 spinulose. 



The first syzygy is between brachials 3 + 4, the second from 10 to 15 brachials 

 beyond, and the distal intcrsyzygial interval is, with remarkable imiformity, 5 mus- 

 cular articulations. 



The pinnules are rather slender. Pi is about 17 mm. long and consists of 45 

 segments, of which the terminal 10 bear teeth. P2 is shorter, with about 35 segments 

 and a comb of 10 teeth. P3 is remarkably short and weak, scarcely 5 mm. long and 

 consists of only 18-20 segments. It has a well-marked comb of 7 segments. The 

 following pinnules, which are without combs, gradually increase in length to 10 mm. 

 or more and are composed of about 20 segments, none of which are conspicuously 

 spinulose, though the terminal ones are more or less so; their basal segments are 

 notably triangular. 



The disk is lacking. 



The color of the dry specimen is uniformly pale fawn, with the ventral siu-face 

 of the arms and pinnules brownish black. 



Remarks. — Dr. H. L. Clark said there is no doubt that this species is very near 

 C. briareus, but after comparison with numerous specimens of the latter he was 

 unwilling to refer it to that species. 



He remarked that the color is naturally the most striking difference, but of course 

 is the least significant. Nevertheless, it is noteworthy that all recorded specimens 

 of C. briareus and all of the 30 specimens at hand (at the Museum of Comparative 

 Zoology) are blackish brown, brownish black, or purplish black. One recorded 

 from Western Australia by A. H. Clark has lighter lines on the arms. 



Aside from the color, the flaring distal edges of the short elements of the division, 

 series and of the brachials in C. perplexum are quite different fi'om those of C. briareun 

 while the smoothness of the brachials and pinnules is noticeable when contrasted 

 with the rough arms of C. briareus. 



Just why Doctor Clark compared this form with the very ditt'erent briareus, from 

 which it is at once distinguished by the small number of arms, the eversion of the 

 distal edges of the elements of the division scries, the smoothness of the arm bases, 

 and the occurrence of functional cirri, it is diflficult to see. 



It is very closely allied to weberi, of which it appears to be the southern repre- 

 sentative, but with which it may prove to be identical. 



Locality. — Eleven miles south by east of Ballina, New South Wales; 49-51 

 meters; Endeavour [H. L. Clark, 1916]. 



History. — This species is as yet known only from the type specimen. 



