186 EXPLANATION OF THE PLATES. 



Plate V. — Fig. 1. Gigartina exasperata, Harv. & Bail. ; large 

 specimen, of the natural size. Fig. 2. Section of the 

 frond, magnified. 



Plate VI. — Fig. 1. Nostoc expansum, Harv. & Bail. ; natural size. 



Fig. 2. Magnified section of the frond. 

 " Fig. 3. Gigartina mollis, Harv. & Bail. ; frond, of the 



natural size. Fig. 4. Portion of a cross-section of the 



same, much magnified. 

 " Fig. 5. Gymnogongrus vermicularis, J. Ag. ; not 



magnified. Fig. 6. Cross-section of the same, much 



magnified. 



,L' Q l 



Plate VII. — Fig. 1. Chondrus exilis, Harv. & Bail. ; frond, not 



magnified. Fig. 2. Portion of the same, magnified. 

 " Fig. 3. Ectocarpus namulosus, Harv. & Bail. ; a tuft 



of the plant, of the natural size. Fig. 4. Filament 



and branches, magnified. Fig. 5. Branch and spores, 



much magnified. 

 " Fig. 6. Chondrus uncialis, Harv. & Bail. ; frond, not 



magnified. Fig. 7. Portion of the same, magnified. 

 " Fig. 8. Gractlaria filiformis, Harv. & Bail.; frond, of 



the natural size. Fig. 9. Cross-section of the same, 



magnified. 

 Fig. 10. Gymnogongrus dendroides, Harv. & Bail; a 



specimen from Hawaii. Fig. 11. A specimen from 



Callao. 

 Fig. 12. Gelidium rigidum, var. unilaterale, Harv. & 



Bail. ; frond, not magnified. Fig. 13. Magnified 



cross-section of the same. 



Plate VIII. — Fig. 1. Caulerpa Pickeringii, Harv. & Bail. ; plant, of 

 the natural size. Fig. 2. Magnified cross-section, 

 showing the arrangement of the verticillate leaves. 

 Fig. 3. A leaf, still more magnified. 



" Fig. 4. Caulerpa falcifolia, Harv. & Bail. ; natural 



size. Fig. 5. Leaves, magnified. 



" Fig. 6. Dictyota bidentata, Harv. & Bail. ; a frond, not 



