THE ALGAE OF BERMUDA. 37 



In an artificial fresh water reservoir near Spanish Rock, Jan., Hervey, 

 Aug., ColHns. Type in herb. ColHns, No. 7812. 



The basal cell is depressed-globose, 20-24 ^ diam., 12-16 /x high; 

 the first cell above is Q-8 fx diam., 2-3 diam. long; the filament may 

 continue of the same diameter, or may increase up to 12 /j., the cells 

 1-2 diam. long; occasionally the diam. reaches 20 fx, the cells about 

 one diam. long and moniliform; at any point a larger filament may 

 suddenly change to the smaller diameter, a cell of 8-10 fx following a 

 cell of 12-20 fx. Oogonia were not uncommon, but were very gener- 

 ally abortive; in the few instances where they seemed normal they 

 were regularly globose, and contained a globose oospore, quite filling 

 the oogonium, of orange yellow color. The division of the oogonium 

 was median or slightly higher; no antheridia were seen. 



The study being made from formalin material, the development of 

 the zoospores could not be followed, but they must have been pro- 

 duced in immense numbers. Cells of Pithophora kewensis were seen, 

 completely covered with zoospores which had affixed themselves, but 

 still retained the spherical form, and were 16-24 fx diam.; the appear- 

 ance was much like that of a filament of Lynghya covered with Xeno- 

 coccus, as shown in Bornet & Thuret, 1880, PI. XXVI, fig. 1. The 

 zoospores seemed to secrete some adhesive substance from the cell 

 wall, forming a sort of collar underneath the cell, extending beyond 

 the diameter of the cell, so as to be visible from above as well as from 

 the side. Something similar is seen in Chantransia collopoda Rosen- 

 vinge, 1898, fig. 10, A. As the densely packed zoospores germinate, 

 the host soon becomes indistinguishable, the sporelings forming a 

 bristly mass, to the filaments of which more zoospores attach them- 

 selves, adhering to the young Ocdogonium filaments in the same way 

 as to the Pithophora. It seems probable, however, that often the 

 zoospores adhere to each other in a larger or smaller rounded mass; 

 when they germinate the radiating filaments form an echinate body, 

 which is different from anything we find recorded for the genus, except 

 the figures of 0. pachycmdrium in Wolle, 1887, PI. LXXIII, figs. 38 and 

 39. 



These figures though rude and in no way showing the evolution of 

 the cluster, give a fair idea of the appearance. These masses often 

 contain hundreds, probably thousands of spores, and before germi- 

 nation has much progressed, look like bits of fish roe. In the material 

 of No. 7812 the Pithophora appeared to be fairly smothered by the 

 Oedogonium, many of the cells dead; the greater part of the spores 

 were attached to Oedogonium filaments or to each other; in No. 7368 



