A MONOGRAPH OF THE EXISTING CEINOIDS 67 



On the basis of 15 specimens from Mjoberg's stations 4, 10, and 13 Dr. Torsten 

 Gisl6n redescribed adeonae as follows: 



The centrodorsal is discoidal to hemispherical, the bare dorsal pole a httle convex 

 with small pits and knots, 2.5 mm. in diameter. The cirri are arranged in two rows. 



The cirri are XIX-XXXV, 19-.32 (22-32 in the upper and 19-29 in the lower 

 row), about 12 mm. long. The first segment is short. The four following are broader 

 than long, and those succeeding are about as long as broad, or a little longer than 

 broad. The penultimate segment is shorter again. The outer segments are provided 

 with two groups of processes, a proximal transverse ridge and a distal row of spines. 

 The proximal transverse ridge is straight and even, and is situated at the proximal 

 border of the segment. The distal transverse ridge is situated on the distal part of 

 the segment and is somewhat curved with irregular protuberances at the margin; 

 on the distal segments these are prolonged into two blunt lateral spines. The proximal 

 transverse ridge usually appears somewhat before the distal one. The distal borders 

 of the segments on their ventral side are bent a httle outward, which gives the cirri 

 a somewhat imeven margin. The opposmg spine occupies only a portion of the 

 dorsal surface of the penultimate segment, and reaches a height equal to one-third 

 the width of the segment. The proximal transverse ridge often still remains on the 

 penultimate segment. The terminal claw is stout, strongly cm-ved, and about as 

 long as the penultimate segment. Fully developed cirri usually show the proximal 

 transverse ridge on about the fifth and the distal on the eighth-thirteenth segments. 

 The dorsal processes are developed first on the proximal segments, and last of all on 

 the distal ones. 



The radials are visible as narrow bands, or are concealed by the centrodorsal 

 except in the interradial angles of the calyx. The median portion has one or more 

 distinct tubercles, and similar tubercles are often found on the proximal portion of 

 the IBri. The IBr, are three times as broad as long, and are united in their basal 

 halves. With the IBrj (axillaries) they form a synarthrial tubercle which is separated 

 from the remaining portion of the ossicles by shallow grooves. The distal angle of 

 the IBr2 is less than 90°. 



The 10 arms are 50-70 mm. long. The first brachials are interiorly miited 

 basaUy, and form a synarthrial tubercle with the second. The ossicles from the IBr, 

 to the second brachials have ventrolateral flanges that encircle a narrow U-shaped 

 gap between the arms. The fourth-ninth brachials have promment and swollen 

 distal borders. The prominence on the fourth brachial is most strongly developed 

 interiorly, so that there is a prommence directed backward alternately on the exterior 

 and interior of the arm. In addition, on these segments proximaDy developed 

 tubercles often form an indistmct median ridge. After the second syzygy the brachials 

 grow smoother and are wedge-shaped. 



The first sy/.ygy is between brachials 3 + 4, and the second is from the eighth 

 to the eleventh segment. The distal intersyzj'gial interval is 4 muscular articulations, 

 syzygies occurring, for mstance, between bracliials 9-|-10, 14 + 15, 19 + 20, etc. 



Pi is from 10 to 15 mm. long with 13-20 segmpiits. The first segment is about 

 as long as broad, the second is half again as long as broad, and the third, fourth, and 

 fifth are more than twice as long as broad; the segments following are shorter again, 

 always, however, a httle longer than broad. The piimule is smooth, strongly com- 



