A MONOGRAPH OF THE EXISTING CRINOIDS 253 



and one-half times as long as broad; the distal segments are a little longer still and 

 taper distally. P 2 is 4 mm. (probably originally 4.5 mm.) long with about 10 seg- 

 ments, stouter and stiff er than P,, the tips arching over the surface of the disk; the 

 third segment is three times as long as broad, and the longest segments are four times 

 as long as broad. P 3 is 2.5 mm. long with about 8 segments. P 8 is 3.5 mm. long with 

 11 segments. P, is 4.5 mm. long with 11 segments. From this pinnule onward there 

 are well-developed gonads on the third-fifth segments. The distal pinnules are 6 mm. 

 long with 17 segments of which the first is twice as broad as long, the second is half 

 again as long as broad, the third is three times as long as broad, and the longest are 

 from four to five times as long as broad. The disk extends to the sixth brachial. 

 The anal tube, which is distinctly visible between the arms, is long and naked. The 

 color in alcohol is whitish, the perisome and the soft parts of the pinnules brown, and 

 the pinnules light brown. 



In another specimen from Mortensen's station 57 the cirri are XVI, 17, 6.5 mm. 

 long, and are clinging to a hydroid. The arms are about 50 mm. long. P a is absent 

 on all the arms; P 4 , P<j, and sometimes P 5 are absent. 



In a third specimen from Mortensen's station 57 the centrodorsal is a flattened 

 hemisphere with some interradial pits. The cirri are XII, 14-18, up to 6.5 mm. 

 long. No basals are visible. The arms are 35+ mm. in length. The pinnulation is 

 as before, but sometimes P 3 and P c are also absent. The disk has been lost. 



Professor Gisl^n said that with its long brachials and rather moniliform arm 

 bases, and with the few-jointed cirri lacking dorsal spines or carination, this species 

 has a very close resemblance to the Antedoninae. As P a is absent, one might think 

 of the Perometrinae, but the forms included in that subfamily are characterized by 

 much longer cirri with more segments which, besides, are provided with spines. The 

 other subfamily of Antedonidae to be considered in this connection is the Ante- 

 doninae. Within this subfamily Andrometra is the only genus that approaches the 

 new form in the proportions between the proximal pinnules. But in Andrometra the 

 the centrodorsal is conical and the characters of the proximal arm parts are very 

 different. Besides, the defective pinnulation would be something unique within 

 the Antedoninae. He concluded that in spite of a very antedonid appearance this 

 new form is probably most correctly to be ranged within the Colobometridae. 



He noted that the cirri, while in appearance the segments because of the distal 

 flaring suggest the Antedoninae, resemble the cirri in some species of Decametra. 

 Moreover, only very rarely in the Antedoninae is P 2 the longest pinnule, while hi the 

 Colobometridae this is a very usual feature. The curious pinnulation, he said, may 

 be partly an adolescent phenomenon, since hi the largest specimen the distal pinnule 

 gap is filled up on some arms. But if this is the case it is quite unique, for it would 

 be expected that the pinnule gaps would be filled before the gonads become swollen. 

 He remarked that even if full grown individuals should prove to have complete 

 pinnulation the new genus is easily distinguished from all other comatulid genera 

 known by the following features: Hemispherical centrodorsal, few and short cirrus 

 segments without spines but with indistinct distal collars, long jointed and knobby 

 arms, and very long but smooth pinnulars, P 2 being the longest pinnule, and P, 

 being absent. 



