PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 657 



The first two segments of all the pinnules are short; the others are longer than 

 broad and may be very elongated; their distal edges are strongly flared and spiny so 

 that the joints have a swollen appearance. The oral pinnules are the longest, nearly 

 twice as long as the first genital ones and about one and a third tunes as long as the 

 outer pinnules. PI is broken in every case. P ft , P 2 and P b are of 18 to 19 segments, 

 8 mm. long. P 3 is the first genital; it has about 10 segments and is about 4 mm. long; 

 P 5 is similar but with a larger gonad; P 6 has 14 segments about 6 mm. long, and P 8 , tin* 

 last genital pinnule, is of 17 segments, 6 mm. long. The ambulacra! furrow is only 

 present on the outer genital pinnules. The distal pinnules have about 17 segments and 

 measure about 6 mm. in length. The elongated segments of the oral pinnules are up 

 to three times as long as broad; those of the lower genital pinnules may be relatively 

 longer; those of the distalmost pinnules are shorter, only up to twice as long as broad. 



Sacculi are fairly conspicuous, more numerous and more regularly arranged on the 

 outer than on the genital pinnules. There are no side or cover plates along the pinnule 

 ambulacra, but some of the tentacles have numbers of rodlike spicules. 



The color in spirit was pale straw, except for the syzygial pairs which were dusky 

 and gave a banded effect to the arm. 



This subspecies is also brood protecting. The embryos undergo their development 

 in marsupia placed on the aboral sides of the genital pinnules, alongside the ovaries. 

 The ovaries and marsupia of the middle genital pinnules lie along the third to fifth 

 segments. Both can be seen at the same time from the outside and their walls are so 

 thin as to be transparent. The ambulacra! furrow of the outer genital pinnules lies 

 along the dividing line on the ventral side. The wall of each marsupium is split open 

 for the whole of its length exposing the embryos within. There are 10 or 11 in each 

 pouch, arranged in one layer and lightly attached to the floor of the chamber, the 

 dividing septum, by an extremely thin membrane. They are roughly spherical, except 

 that one end is strongly flattened to form the suctorial disk, from 0.21 to 0.24 mm. in 

 diameter. All the embryos seem to be at the same developmental stage. The vestib- 

 ulum is clearly marked. There are 4 bands of cilia, one lying around the edge of the 

 suctorial disk. The skeleton consists of about 18 stem joints and a larger terminal 

 plate, and of five oral and five basals, which are openly branching and may be nearly 

 in contact. 



Female from station 1948, which is much smaller: 



The centrodorsal is a low rounded cone, with a large bare dorsal pole. The cirrus 

 sockets appear to be arranged partly in columns and partly hi alternating rows. 



The cirri are L, 12-17. They are smaller than those of the first specimen and the 

 opposing spine is reduced. 



The distal edges of the lower brachials are more strongly everted and spiny than 

 in the other specimen. 



The pinnules are also similar but P 2 is the first genital pinnule. PI has 18 segments, 

 about 5 mm. long. The segments after the second are just over twice as long as broad. 

 P 2 has 8 segments, 2.5 to 3 mm. long. The third and following segments are nearly 

 four times as long as broad. The gonad lies along the third to fifth segments. P< with 

 10 segments is 3.5 mm. long and its ovary and marsupium extend to the sixth segment. 

 P a is the last genital pinnule. 



There are rodlike side and cover plates with perforated or branched ends along 

 some of the pinnule ambulacra and some of the tentacles contain large numbers of 

 smooth and knobbed rodlike spicules. 



