PLATE 17. 



Collinsiella tuberculata Setchell and Gardner gen. et sp. nov. 



1 . Habit of No. 403, N.L.G., from Whidbey Island. (X 40) 



2. Vertical section through one of the fronds. (Zeiss 2 X A) 



3. Dissection of a portion of the vertical section which has been treated 



with Chloriodide of Zinc, to show the branching. The cell con- 

 tents are much shrunken. (Zeiss 2 X D) 



4. Tangential section at the surface to show the division planes. 



(Zeiss 2 X D) 



5. Young terminal cell, untreated, showing the chromatophore lining 



the wall and the solitary pyrenoid. (Zeiss 2 ■ D) 



6. Similar view of an older cell, showing the vacuolate appearance of 



the chromatophore. (Zeiss 2 X D) 



7. Similar view of still older cell, showing the decrease in size of the 



chromatophore and a double pyrenoid. (Zeiss 2 X D) 



Codium Ritteri Setchell and Gardner sp. nov. 



8. Habit of the type specimen, (nat. size) 



9. A common shape of the adult utricle. (Zeiss 2 X A) 



10. A common shape of the adult utricle. (Zeiss 2 X A) 



11. An uncommon, yet not rare, shape of the adult utricle. (Zeiss 2 X A) 



Rhodochorton subimmersum Setchell and Gardner sp. nov. 



12. A section through the host plant, showing the horizontal immersed 



filament of the Rhodochorton and the vertical emergent fila- 

 ments, as well as the terminal tetrasporangia. Specimen No. 289, 

 N.L.G., from Whidbey Island. (Zeiss 2 X D) 



All the figures of this plate were drawn under the direction of W. A. 

 Setchell by H. N. Bagley. The size varies proportionally to the original, 

 and in the case of microscopic details we shall mention here, as well as under 

 the remaining figures, only the combination of the lenses used. The drawings 

 have all been reduced to one-half the original diameter, but the magnifica- 

 tions, where given, refer to the figures as reduced. 



L398] 



