REPORT ON THE CRINOIDEA. 157 



in Antedon longipinna, Antedon tenella, and Antedon exigua (PI. XXX. fig. 2 ; PI. 

 XXXI. fig. 4 ; PI. XXXII. fig. 4). On the other hand, in Antedon eschrichti and its 

 allies the first two or three pairs of pinnules consist of short and wide joints (PI. XXIV. 

 figs. 1, 2, 7-9; PI. XXV. figs. 1, 2 ; PI. XXVII. figs. 8, 9, 11, 12, 14). The species of 

 the Eschrichti-grou-p are exclusively confined to the Atlantic and Circumpolar Seas, 

 but do not extend downwards below 650 fathoms. The Basicnrva-growp, however, is 

 principally limited to the Pacific, ranging from 140 to 1350 fathoms. But there are 

 three Atlantic species which occur at depths of 420 to 1600 fathoms. On the other hand 

 the members of the TeneZZa-group are chiefly confined to the Arctic Ocean, the Atlantic, 

 and the Southern Sea. Antedon prolixa is one of the two northernmost Comatulse 

 known ; and two more {Antedon hirsutq and Antedon exigua) reach further south than 

 any others except Antedon australis and Antedon antarctica. Of the remaining fourteen 

 species only five occur in the Pacific ; four of them range between 150 and 775 fathoms ; 

 while the fifth, obtained at 2900 fathoms in the North Pacific (Station 244), was also 

 found at 2600 fathoms in the Southern Ocean (Station 160). These were the two 

 deepest stations at which Comatulse were met with. The next deepest (1600 fathoms) 

 in the Southern Ocean (Station 147) yielded two more species of the Tenella -group, 

 the remaining members of which are confined to the Atlantic. One or two of them 

 are littoral species, like Antedon rosacea itself, and Antedon diibeni, but this is not 

 the case with the Pacific members of the group, which are not known as yet to occur 

 above 150 fathoms. 



With a few exceptions, then, the Tenella-growp may be regarded as especially 

 characteristic of the Atlantic and Circumpolar Seas, just as the Basicurva-gvowp is 

 chiefly confined to the Western Pacific ; and in each case the exceptional species belong 

 to the continental or abyssal, but never to the littoral fauna. 



Long-jointed lower pinnules. 



A. Forty or more long cirrus-joints. 



I. Second pinnule as long as the first, . . . .1. phalangium, Mull, sp. 



II. Second pinnule smaller than the first. 



a. Axillaries longer than wide; second radials very deeply 



incised, ....... 2. hi/strix, n. sp. 



b. Axillaries as wide or wider than long; second radials incised, 



but not very deeply so, . . . . . prolixa, Duncan and Sladen. 



B. Fifteen to thirty cirrus-joints. 



I. Second pinnule distinctly smaller than the first. 



a. Cirrus-joints mostly longer than wide, the lower ones very 

 much so. 

 1. First pinnule nearly three times as long as the second ; 



syzygial interval two joints, . . .3. tenella, Retzius, sp. 



