i68 DISCOVERY REPORTS 



The distal edges of the costals are everted. The distal edges of the lower brachials are 

 more strongly everted and spiny than in the other specimen. 



The pinnules are generally similar to those of the specimen from St. 156, but there 

 are differences: there is only one oral pinnule, for Pg carries an ovary and brood-pouch; 

 the segments of the pinnules, particularly of the orals, are less elongated. Nevertheless 

 Pj is about twice as long as the first genital, Pg . The segments of the pinnules have 

 expanded and spiny distal ends. Pg is the lowest pinnule to have an ambulacral furrow. 



Pj is of 18 segments, about 5 mm. long. The third and succeeding segments are a little 

 more than twice as long as broad. P2 is of 8 segments, 2-5-3 rnni- lo'ig- The first seg- 

 ment is slightly longer than broad, the second nearly twice as long as broad. The re- 

 maining segments are nearly four times as long as broad. The gonad lies along the third 

 to fifth segments. No complete P3 can be seen. P4 is of 10 segments, 3-5 mm. long, and 

 is similar to P2 except that the ovary and brood-pouch lie along the third to sixth 

 segments. Pe is the last genital pinnule. It is of more than 12 segments and more than 

 4 mm. long. It carries a very small ovary and brood-pouch on the third and fourth 

 segments. The earlier of the distal pinnules are of 14 segments and more than 4 mm. long. 



Sacculi are numerous and conspicuous. 



There are rod-like side- or 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 rod-like spicules. 



The first four or five segments of the cirri are yellow ; the remainder are of a dusky 

 hue. The rest of the specimen is overlaid with a light yellow tinge. 



An enormous brood-pouch lies alongside each ovary and runs farther than it distally. 

 The large numbers of embryos that the brood-pouches contain may clearly be seen 

 through their thin walls ; the walls of many are ruptured. The ovary lies a little to the 

 adoral side of the pinnule. The brood-pouch hes on the aboral side, nearest the arm and 

 the outside, but distally it passes also across the ventral side of the ovary and may extend 

 farther adorally than the ovary, so that it is crescent- or comma-shaped. The embryos 

 in the brood-pouch are in various stages of development, but the most highly developed 

 are always in the distal part ; if any part of the brood-pouch is ruptured it is this ; which 

 makes it appear that the ruptures may be natural, freeing the fully formed larvae. The 

 relationships of the ovary and brood-pouch are shown in Fig. 10/7. 



There are about seventeen embryos in a large brood-pouch. They lie not in a single 

 layer, and are not all at the same stage of development, as in the specimen from St. 156 

 and in Phrixometra longipinna: they are arranged in an irregular double layer and are 

 in various stages of development, the most highly developed being at the distal end 

 (see above). Presumably the eggs pass from the ovary into the brood-pouch at the 

 proximal end. The fully formed larvae are similar to those of the specimen from St. 156, 

 but they are considerably bigger, o-30-o-36 mm. long. 



I have no doubt that the three very broken males from this station are of the same 

 species. They do however differ from the female in some ways. They are larger and the 



