PART 5 



A MONOGRAPH OF THE EXISTING CRINOIDS 



659 



Diagnostic features. The cirri have up to 20 segments, of which the longest are 

 about three times as broad in the peripheral cirri and the distal part of each cirrus is 

 distinctly wider dorsoventrally than the proximal part; P! has up to 30 segments; 

 P 2 , the first genital pinnule, is shorter, with fewer but longer segments. 



Description [modified by A.M.C.]. The three syntypes are ah 1 badly broken. 

 The one from station 145 has no cirri and in the two from shallower water off Marion 

 Island no complete peripheral cirri remain and the proximal pinnules are all more or 

 less broken. All three specimens appear to be males though the gonads are hard and 

 shrunken in the one from station 145. 



The centrodorsal in the syntype lacking cirri is hemispherical, 2.2 mm. in basal 

 diameter and 1.4 mm. in vertical height, viewed interradially. The periphery is pro- 

 duced interradially. There are L-LX cirrus sockets all over the centrodorsal except 

 for a small rough central patch. No special arrangement of the sockets is evident 

 though some tend to form vertical lines. There are about four sockets in each line. 



No complete peripheral cirrus remains ; according to Carpenter and to a manuscript 

 note by Dr. Dilwyn John, they had about 20 segments. A stump of seven segments 

 has the longest segment about three times as long as the median width. A cirrus 

 once removed from the periphery has 17 segments and is about 7 mm. long. The basal 

 segments are relatively more slender than those of the peripheral stump, the longest 

 (the fifth) being nearly four times as long as wide. The five or six segments before the 

 penultimate are distinctly widened dorsoventrally relative to the first nine or ten 

 segments, at the same time being considerably shorter, but the antepenultimate is still 

 a little longer than wide. The opposing spine is moderate in size and the terminal 

 claw curved and acute. The peripheral cirri would have had all the segments relatively 

 shorter, to judge from the proximal part, so that the distal segments would probably 

 not have been longer than wide. The apical cirri are much smaller and more slender. 



a 



FIGURE 37. Phrixometra exigua (P. H. Carpenter), syntype: a, Lateral view of calyx; 

 b, proximal part of peripheral cirrus; c, cirrus from second row above periphery; 

 d, PI (incomplete). 

 656-62267 13 



