EXPLANATION OF THE PLATES. 



Plate I. — Fig. 1. Sargassum Sinclairii, Hook. & Harv. ; a speci- 

 men, of the natural size. Fig. 2. A single leaf. Fig. 



3. Leaves and air-vessels. Figs. 4, 5. Air-vessels. 

 Fig. 6. Cross-section of the stem near the base. 



Plate II. — Fig. 1. Apophlcea Sinclairii, Harv. ; drawn from a 

 dried specimen. The plant swells much when moist- 

 ened. Fig. 2. Portion of a transverse section, show- 

 ing one of the numerous conceptacles, much magni- 

 fied. 

 u Fig. 3. Notheia anomala, Harv. & Bail. ; a plant, of the 



natural size, parasitic on Hormosira. Fig. 4. A 

 branch, magnified. Fig. 5. A perispore, with para- 

 nemata. Fig. 6. A cross-section, showing a scaphi- 

 dium; much magnified. 



Plate III. — Fig. 1. Irid^ea lusoria, Harv. ; a large specimen. Fig. 

 2. Portion of a cross-section of the frond, much raa°-- 

 nified, showing the position of the spores. Figs. 3, 



4. Spores, still more magnified. 



Plate IV. — Fig. 1. Rhodymenia Wilkesii, Harv. & Bail.; a large 

 specimen, of the natural size. Fig. 2. Magnified sec- 

 tion through one of the coccidia. Fig. 3. Magnified 

 section of the frond. 



47 



