PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 29 



dorsal pole is clearly marked with several hollows which are presumably obsolete 

 cuTus sockets. 



The cirri are X-XX, 35-47 (usually 35-40), from 15 to 25 mm. long. In the largest 

 syntype the first segment of the peripheral cirri is broader than long, the second is 

 nearly as long as broad, the fourth to the tenth are just under half again as long as 

 broad, and those following decrease slowly in length, the last 15 to 20 being slightly 

 broader than long, or about as long as broad. In the middle portion the cirri are 

 circular in cross section, but on the last 10 to 20 segments the dorsal surface becomes 

 broadly flattened and develops a number of strong longitudinal striations. This por- 

 tion of the cirrus is exceedingly flexible and is capable of being coiled into a spiral, 

 whereas the proximal two-thirds is more rigid and usually straight in the preserved 

 specimens. In the specimens with arm length 25 mm. or less, the segments are propor- 

 tionately longer and the longest may be over one and a half times as long as broad. 



The radials are short with the distal border strongly and evenly concave, and are 

 about three times as long interradially as in the midradial line. They are completely 

 joined uiterradially. The IBri are nearly three times as broad as the median length, 

 with the lateral borders produced and the lateral edges straight and parallel; the distal 

 border is straight or shghtly and evenly concave. The IBrj (axillaries) are 5-sided, 

 and are nearly or quite twice as broad as long. The two lateral sides are about half 

 as long as the median length and are parallel, continuing the parallel sides of the IBri. 

 The proximal border is slightly convex, following the curvature of the distal border 

 of the IBri, and the two distal sides, which are sUghtly concave, make with each other 

 an angle of about 90°. The straight sides of the division series extend in a shght 

 lateral flange. 



The 10 arms are up to 30 mm. long. The proximal brachials are nearly rectangular 

 in dorsal view ^\'ith the proximal and distal sides almost parallel. 



Syzygies usually occur between brachials 3+4, 7 + 8, and 12 + 13, and distally 

 at intervals of two muscular articulations, but the second and third are variable in 

 position. 



Pj is up to 6.0 mm. long, rather stout basally but evenly and graduallj' tapering 

 to a fine point. It is composed of 8 to 10 segments of which the first is about as long 

 as broad, the second is somewhat over twice as long as broad, and those following are 

 nearly or quite four times as long as broad; the ventrolateral ends of the distal borders 

 of the segments are slightly produced. In a specimen of arm length 15 mm., Pi is 2.0 

 mm. long with 7 segments. 



P^ is similar but more or less smaller and shorter, often very short, with 6 or 7 

 segments. 



P2 is the first genital pinnule. It is up to 3.0 mm. long, with 10 to 16 segments, 

 more slender and much more flexible than Pi; most of the segments are about twice as 

 long as broad and very slightly constricted centrally. 



The genital pinnules extend as far as P]2 in the largest sjmtype. The marsupia 

 of the females are on the aboral sides of the pinnules. Each of the foiu- opened contained 

 only one or two embryos in process of development. 



The distal pinnules are rather abruptly longer than the genital pinnules, 3.7 mm. 

 long; they are composed of 16 segments, mostly about twice as long as broad and slightly 

 constricted centrally, the terminal bearing a number of sharp recurved spines dorsally, 



