A MONOGRAPH OF THE EXISTING CRINOIDS 143 



Aciinometra pulchella (part) P. H. Carpenter, Bull. Mus. Comp. Zool., vol. 9, No. 4, 1881, p. 160 

 (the rough armed specimens, and those from Blake station 269 mentioned in the second 

 footnote) . 



Adinometra alata Hartlaub, Mem. Mus. Comp. Zool., vol. 27, No. 4, 1912, pp. 280, 281, 413 

 ( = echinoptera) . 



Aciinometra echinoptera var. pulchella subvar. alata Hartlaub, Mem. Mus. Comp. Zool., vol. 27, 

 No. 4, 1912, p. 419 (discussion); p. 440 (Biafce stations 249, 106, 277, 298, 294, 224, 269); pi. 18, 

 figs. 9 (part), 10, 14, 15, 16. 



Neocomatella ornata A. H. Clark, Proc. Biol. Soc. Washington, vol. 30, 1917, p. 63 (detailed de- 

 scription; Albatross station 2321). 



Neocomatella alata A. H. Clark, Univ. Iowa, Studies in Nat Hist., vol. 9, No. 5, 1921, pp. 9-11 

 (occurrence at Barbados); The Danish Ingolf-Exp^A., vol. 4, No. 5, Crinoidea, 1923, p. 38 

 (range) . 



Diagnostic features. — The distal edges of the brachials are produced and everted, 

 standing out almost at right angles to the axis of the arm, and are bordered with 

 rather coarse spines; this modification of the distal edges of the brachials increases 

 from the second to the eighth after which it is very conspicuous. When this is well 

 developed the profile of the arms recalls that of the arms in the more carinate varie- 

 ties of Tropiometra pida. 



Description. — The centrodorsal is discoidal, with a broad, flat, finely pitted 

 polar area 4 mm. in diameter. 



The cirri are XIX, 19-21, about 20 mm. long. The first segment is very short, 

 the second is somewhat longer, the third is about as long as broad, and the fourth 

 and fifth are the longest, about twice as long as broad, the fifth being slightly longer 

 than the fourth. The fifth is a transition segment, proximally dull, like the preced- 

 ing, but highly polished in its distal fourth. The sixth segment is about as long as 

 the fourth, and those following gradually decrease in length, becoming about as long 

 as broad on the eighth or ninth and beyond slightly broader than long. The transi- 

 tion and following segments have the distal dorsal edge prominent. After the 

 seventh the dorsal side rises evenly from the base to the tip so that the segments are 

 trapezoidal in lateral view, which gives the cu'ri a serrate dorsal profile. After the 

 eleventh segment the proximal half of the dorsal side becomes rather less produced, 

 but the distal half rather more so, so that in lateral view there appears to be a low, 

 broadly rounded dorsal spine on each segment which arises from somewhat more than 

 the distal half of the dorsal surface. In the more compressed distal segments the 

 produced distal dorsal edge, at first crescentic in end view, becomes narrower, but 

 does not lose in height, so that it changes to rounded triangular and, as less of the 

 dorsal surface is involved, appears tubercular. A faint median carination is traceable 

 on the distal half of the later segments. The opposing spine is very low, median in 

 position, involving the entire surface of the penultimate segment, rather slender and 

 moderately curved. 



The ends of the basal rays are just visible in the angles of the calyx. 



The radials are only slightly visible in the interradial angles over the ends of the 

 basal rays. The IBri are exceedingly short and bandlike, in lateral apposition for 

 rather more than their basal half, but separated by a U-shaped gap distally. The 

 IBr2 (axillaries) are broadly pentagonal, appro.ximately twice as broad as long, with 

 the lateral edges about as long as those of the IBr,. The IIBr series are 2. The 



