A MONOGRAPH OF THE EXISTING CRINOIDS 581 



Diagnostic features. The broad discoidal centrodorsal with a flut dorsal pole 

 bearing numerous rather slender cirri with usually 18-20 segments of which the longest 

 are twice as long as broad, from 10 to 14 mrn. (usually about 12 mm.) in length, the 

 15-28 (usually about 20) rather short and rapidly tapering arms which are from 60 

 to 130 mm. (but rarely over 100 mm.) long, and the curiously pointed axillaries make 

 this species an easy one to recognize. Aside from its immediate relatives in Tas- 

 mania and New Zealand, it resembles most closely the much smaller South African 

 C. wahlbergii. 



Description. The centrodorsal is discoidal, broad, the polar area 4 mm. in diam- 

 eter and flat. The cirrus sockets are arranged in one and a more or less complete 

 second crowded marginal row. 



The cirri are XXV-XXXVII, 13-20 (usually 17-18), 12 mm. long, and remark- 

 ably slender. The first 2 segments are short, twice as broad as long, the third is 

 half again as long as broad, and the next 3 or 4 segments are twice as long as broad. 

 The following segments decrease rapidly in length so that the outermost 7 or 8 are 

 from half again to twice as broad as long. The third and following segments have 

 somewhat expanded articulations, this character decreasing as the segments become 

 shorter. In the proximal portion the cirri are well rounded in cross section, but they 

 become laterally flattened on the short distal segments, here appearing somewhat 

 broader in lateral view. The seventh is a more or less marked transition segment; 

 this and the following have the distal dorsal edge slightly thickened, this thickening 

 soon becoming transformed into a small subterminal tubercle. The opposing spine 

 is minute, with the apex subterminal. The terminal claw is somewhat longer than 

 the penultimate segment, and is stout and strongly curved. 



The radials are concealed, except in the interradial angles of the calyx. The IBr, 

 are very short and are partially united laterally. The IBr 2 (axillaries) are triangular, 

 with the anterior angle unusually produced and sharp, and are free laterally. The 

 IIBr series are 4 (3 + 4), usually more or less deficient. The IIIBr series are 4 (3 + 4), 

 but are few in number or absent altogether. The first ossicles after each axillary are 

 united for about their proximal three-fourths, but from that point onward, and ex- 

 teriorly, the division series and arms are well separated. 



The arms are 15-28 in number, from 60 to 100 mm. in length. The first 2 brachials 

 are subequal, wedge-shaped, about two and one-half times as broad as long exteriorly, 

 the second in apposition interiorly. The first syzygial pair (composed of brachials 

 3 + 4) is oblong, two or two and one-half times as broad as long. The next brachial 

 is oblong or slightly wedge-shaped, twice as broad as long. The following brachials 

 are triangular, about twice as broad as long, after the proximal third of the arm be- 

 coming somewhat shorter and more or less wedge-shaped, and terminally somewhat 

 longer. From the eighth or tenth onward the brachials develop rather strongly 

 overlapping distal ends. 



Syzygies occur between brachials 3 + 4, again from between brachials 10 + 11 to 

 between brachials 14 + 15, and distally at intervals of usually 4 muscular articulations. 



The disk is from 9 to 12 mm. in diameter and naked; the mouth is interradial 

 and marginal. 



P D is from 9 to 16 mm. in length and is composed of 30-35 segments, which 

 become about as long as broad on the fifteenth or seventeenth. The lower segments 



