42 COLLINS AND HERVEY. 



ceptible to the eye, it was noticed only in the examination of the 

 C odium material preserved in formalin, so that nothing can be said 

 as to the characters of the supposed zoospores; everything was how- 

 ever similar to the formation and emission of zoospores in the larger 

 and better known species of Chaetornorpha. Emptied cells were 

 common, sometimes every cell of a filament being fertile, even the 

 basal cell; in one instance a filament consisted of a single cell, which 

 had emptied itself through the small round lateral opening. In the 

 form of the cells, thick laminate wall, dense chromatophore with many 

 pyrenoids, the plant is a microscopic copy of forms like C. Linum. 

 Rather curiously, it is the only attached form we find in the islands. 

 The type is in the Collins herbarium. 



2. C. GRACILIS Kiitzing, 1845, p. 203; 1853, p. 17, PI. LIT, fig. 1 

 P. B.-A., No. 2162. Hungry Bay, in dense masses, April, Collins. 



3. C. BRACHYGONA Harvey, 1858, p. 87, PI. XLVI. A; Collins, 

 1909, p. 325. Fish pond, Walsingham, Nov., Hervey, lying loose on 

 the bottom of the pond. 



4. C. LINUM (Fl. Dan.) Kiitzing, 1845, p. 204; C. aerea forma 

 Linum Collins, 1909, p. 325; P. B.-A., No. 1863. Conferva Linum 

 Flora Danica, Vol. V, p. 4, PL DCCLXXI, 1782; Harvey, 1846-51, 

 PL CL. A; Moseley; Rein, as C. geniculata; Hungry Bay, Pool by 

 Moore's calabash tree, April, Collins; Walsingham, Causeway, Nov., 

 Tucker's Town, Dec., Hervey. Common and variable. 



5. C. CRASSA (Ag.) Kiitzing, 1845, p. 204; 1853, p. 19, PL LIX, 

 fig. 11; P. B.-A., No. 1864; Conferva crassa Agardh, 1824, p. 99. 

 Kemp, as Hormotrichum; Pool near Walsingham, April, Lagoon near 

 Fairyland, Aug., Collins. Not always easily distinguishable from 

 C. Linum; study of the various forms in their natural condition if 

 continued over a considerable time, might lead to considerable re- 

 arrangement. 



RHIZOCLONIUM Kiitzing. 



1. Cells rarely under 30 M diam., wall thick, often lamellate. 2. 



1. Cells rarely over 30 /j. diam., usually 10-25 M- 3. 



2. Filaments 50-100 n diam., usually with frequent short branches. 



4. R. Hookeri. 



2. Filaments 33-44 n diam. branching from basal cell only. 



5. R. crassipellitum. 



3. In fresh or slightly brackish water. 2. R. hieroglyphicum. 



3. In salt water. 4. 



4. Cells 20-25 M diam. 3. R. riparium. 



4. Cells 10-15 M diam. 1. R. Kerneri. 



