556 BULLETIN OF THE BUREAU OF FISHERIES. 



sporangium X670. 7. Short exterior filamentsX67o. 8. A branched exterior filament showing lateral 

 and terminal sporangia (one of the emptied lateral sporangia is apparently being refilled or regene- 

 rated from the supporting vegetative cell)X67o. 9. A short exterior filament showing regeneration 

 of a terminal sporangium X 670. 10. Part of a plant showing mode of branching and tortuous course 

 of a part of an interior filament, etc.X67o. n. A short exterior filament bearing immature and 

 emptied sporangia X 670. 12 . An unusually long exterior filament showing long hairs and short secund 

 branchlets (solitary or in pairs) X67<x Drawings by M. A. Howe, from Howe and Hoyt, 1916. 

 PLATE CXIX: Acrochatium affine; i. Spore attached to margin of the Dictyota thallusX4i5- 2 . A spore 

 that has developed a small accessory prostrate basal cell and is also beginning to send up an erect 

 filamentX4i5- 3- Base of .a mature plant showing simple basal cell and two erect filaments, each of 

 which branches from its lowest cell X4i 5. 4- Base of a similar, though larger, plant with four primary 

 erect filaments, each branched at its base, a small cystocarp shown at a X4I5- 5. Base of a plant 

 showing a scarcely enlarged basal cell, short creeping basal filaments, and a single erect filament 

 which has two branches from its lowest cell X4i5- 6. A vertical section through the base of a plant, 

 showing a few small accessory cells that partly cover the primary basal cellX4i5. 7. Base of a 

 plant showing accessory basal cells and three coarse and three slender erect filaments, none of which 

 branches from its lowest cellX4i5. 8. Base of a plant with accessory basal cells and erect filaments 

 of various sizesX4i5- 9- Base of a plant that has developed a small imperfect basal disk, with the 

 original spore still evidentX4i5- 10. Optical section of the margin of the Dictyota thallus showing 

 base of a young plant with a single immersed basal cell and a single erect filament X4i 5. 1 1 . Optical 

 section of the base of a plant showing subpyriform semi-immersed primary basal cell and several 

 superficial smaller secondary cells, some of which send up erect filamentsX4i5. 12. Section 

 through the margin of the Dictyota thallus showing single subpyriform basal cell with penetrating 

 foot X 41 5. 13. Base of a detached plant showing primary basal cell, its penetrating foot, three 

 erect filaments, and two small accessory basal cellsX4is. 14. Section of margin of the Dictyota 

 thallus showing four basal cells of approximately equal size that are more or less immersedX4i5. 

 15. A sporangium terminal on a main branch X 41 5. 16. Sessile lateral sporangia X 41 5. 17. A spo- 

 rangium on a one-celled pedicelX4i5- 18. Procarp and antheridiaX67o. 19. An older procarp 

 with no antheridia apparent in its vicinityX67o. 20. A cystocarp X 670. 21. A typical cell from 

 one of the coarser filamentsX67o. 22. A typical cell from one of the more slender filaments X 670. 

 Drawings by M. A. Howe, from Howe and Hoyt, 1916. 



