56 ULVACE^. 



of the frond, to see the exact cellular structure, owing to the great transparency of the 

 cell-walls, and the facility with which the endochromes are thrown out of their cavities 

 when cross-sections are moistened. 



This is a very distinct species, remarkable for the great diameter of its worm- 

 like filaments, and their clavate form. Notwithstanding its somewhat greater com- 

 plexity of structure, I think there can be no doubt of its near affinity with B. fusco- 

 purpurea. 



Plate XLIX. A. Fig. 1. Bangu vermicularis, the 7iatural size. Fig. 2. A frond mag- 

 nified. Fig. 3. Base; 4. middle portion ; and 5, apex of the same. Fig. 6,7, 8. Trans- 

 verse sections at different heights. Fig. 9 and 10. Radiating endochrome-cells, all 

 highly magnified. 



3. Bangia ciliaris, Carm. ; filaments very minute, (forming a rosy down on the 

 fronds of other Algaj) basifixed, straight ; granules either in a single series, or two or 

 three in each transverse row. Harv. Fhyc. Brit. tab. 322. Chauv. Rech. p. 37- 



Hab. Parasitic on Chondria atropurpurea, at Charleston, S. C, W.H.H. (v. v.) 



This forms a very short, bright, rose-red downy pile on the fronds of the Chondria. 

 Each filament is scarcely the tenth of an inch in length, and consists either of a single 

 row of cells shorter than their diameter ; or of a double or triple series of such cells. 

 Possibly it may be only the very young state of B. fuscopurpurea ; but the habitat 

 is different, and the colour much brighter. 



III. ENTEROMORPHA, Link. 



Frond tubular, membranaceous, green, reticulated. Fructification, granules, com- 

 monly in fours, contained in the cells of the frond. 



The tidjular frond distinguishes this genus from Ulva. The tube varies greatly in 

 width, in different or even in the same species. Sometimes it is of no greater diameter 

 than that of human hair ; and sometimes it is one or two inches across, forming an 

 inflated bag. The species are widely dispersed, extremely variable in ramification and 

 general appearance, and some of them are among the commonest of all littoral algaj. 

 The green stringlike weeds that infest the bottoms of boats and vessels lying in harbour 

 are generally species of this genus, and mostly E. cmnpressa, which is found in all parts 

 of the ocean from the Arctic and Antarctic basins to the Equator. 



