MONOGRAPH OF THE EXISTING CRINOIDS. 561 



The upturned edges of the orals have increased considerably in height. 



The anal plate is distinct. 



In the stage characterized by the presence of the first brachials the penta- 

 crinoids are from 13 mm. to 15 mm. long, the calyx measuring from 1.5 mm. to 2 mm. 



There are 33-35 columnals of which the longest are 0.6 mm. by 0.1 mm. The 

 proximal six or seven are short, but not broader than the succeeding. The central 

 are cylindrical, without distinct traces of the median annulus, and with slightly 

 broadened ends, which are elliptical in end view, the axes of the ellipses on the 

 two ends of each columnal being at right angles to each other. The articular faces 

 resemble those figured by Sars in Hathrometra sarsii, but the fulcral ridge is not 

 so strongly serrate. The distal columnals gradually become shorter, the most 

 distal being only about half as long as wide. The terminal stem plate is rather 

 large and coarsely lobed. 



The radials have formed a completely closed circle, and their apposed lateral 

 edges are of considerable length. They are somewhat thickened at the point 

 where the IB^ are attached. 



The IBr, and IBr, are still long and narrow. 



The basals now end distally in an angle beneath the interradial sutures and 

 thus have become pentagonal. 



The radianal is still distinct. 



The orals still retain their characteristic shape and still reach the edge of 

 the disk. 



The brachials resemble those of H. sarsii at the corresponding stage. 



Side plates, somewhat more branched than those found in the pinnules of the 

 adults, have appeared. 



Fischer recorded two pentacrinoids of this species, which, attached to a Rhyn- 

 chonella, were dredged at the Austro-Hungarian polar station at Jan Mayen. One 

 of these was sent to P. H. Carpenter, who published a figure of it. 



The broken column with 26 segments was 14 mm. long; the crown, with the 

 arms broken at the distal end of the eighth brachials, was 4 mm. long. 



The longest of the five cirri reached almost to the first brachials. 



In the Challenger report Carpenter figured (under the specific name tenella) 

 a pentacrinoid of this species. 



He gives no measurements, but the figure shows a pentacrinoid about 18 mm. 

 long, of which the column, consisting of 23 segments with a considerable part 

 of the distal portion missing, is 12.7 mm. long. 



There is only one cirrus, which reaches to the level of the IBr 2 . 



The column is attached by a slight calcareous expansion at about the thirty- 

 fifth segment (not shown in the figure) to one of the rays of a Rha.bdammina 

 abyssorum, and it then passes on to form two other spreading attachments, with 

 radicular branches sprouting from them over a portion of a tubular hydroid. 



Six or eight long pinnules are developed on each arm, the lowest being on 

 the ninth, tenth, and twelfth brachials. 



Two pentacrinoids which were dredged by the Porcupine in the "cold area" 

 of the Faroe Channel P. H. Carpenter referred to this form. 



