PLATE 20. 



Fig. 16. Crista pacifica, sp. nov. A portion of a young tip of a 

 branch showing the method of branching when the ocecium is low in the 

 internoile, the third member (of.). The first branch of this internode 

 corresponding to the second branch of a typical internode, occurs on the 

 fourth zocecium, the zoeecium alternating with the ocecium (br. i), while the 

 next branch occurs on the seventh zocecium (br. 3), its origin being almost 

 hidden by the ocecial aperture. X 36. 



Fig. 17. C. pacifica. Habit sketch. X 1. 



Fig. 18. Crisia maxima sp. nov. A portion of a branch showing a 

 typical case of the relation between the position of the ocecium and the 

 branching of the ooecial internode. The ocecium being the seventh member 

 of the internode, the first branch (br. 1) occurs on the fifth zocecium, the 

 second branch (br. J) on the eighth zocecium, that member of the internode 

 which pairs with the ocecium; the third branch (br. 3) on the eleventh 

 zooecium, its joint appearing just behind the ocecial aperture (oep.). X 36. 



Fig. 19. C. maa ima. Habit sketch. X 1. 



Fig. 20. Crisia pugeti sp. nov. A portion of a branch showing the 

 ocecium (oe.) with the long flattened tube of the ooeciostome and the ooecio- 

 pore (oep.). X 39. 



Fig. 21. C. pugeti. The upper part of another ovicell from the same 

 colony as that from which fig. 20 was taken, showing a variation in the 

 shape of the tube of the ooeciostome (oest. t.) and the circular ooeciopore 

 (oep.) X 36. 



[274] 



