EXPLANATION OF PLATES. 



TLATK I. 

 J. H. nUde and JV. G. Farlow. 



Fig. 1. Glococapsa crepiditmm, Tliurot. (tOO diain. 



2. Isactis plana, Thnrvt. (U>0 diain. 



3. Spharozi/ija CarmichaeUi, Harv. : «, heterocyst ; ^, ?>, spores. GOO diam. 



4. Lyncjbiia majufivnla, Harv. 400 diam. 



5. Oscillaria aubiiliformis, Ilarv. 500 diaui. 



G. Calothrix conftrvicohi, Ag. : a, a, honuogouia ; h, h, btttTocyvSts; c, cell of host- 

 plaut. 400 diain."* 



PLATE II. 



J. II. Blake and JV. G. Farlow. 



Fig. 1. Ilonnactis Quoyi, (Ag.) Borne t : a, rt, heterocysts. GOO diam. 



2. liivularia aira, Roth : a, a, Leterocysts ; the cross-lines rei)reseiit the gelatinous 



matrix. 500 diam. 

 i. Microcoleu8 chthonoplastes, TLiiret: rt.free tricbomata projecting beyond tbo 



ruptured sbeatb. 500 diam. 

 4. SpiruUna ienuiss'ima, Kiitz. 900 diam. 



PLATE III. 



J. II. Blake and JV. G. Farlow. 



Fig. 1. Ulva Lactuca, (L.) Le Jolis: a, microzoospores which have escaped from mar- 

 ginal cells; by cells in which zoospores are forming ; c, cells from which zoo- 

 spores have escaped. .')00 diam. 



2. lihlzocloniutn r'qHirium, Kiitz. 20 diam. 



3. Cladophora Uetevirens, (D\U\y.) lliirv. 20 diam. 



PLATE IV. 



J. n. Blake and JV. G. Farlow. 



Fig. 1. Bryops'is plumosa^ (Huds.) Ag. ; portion of upper division of the unicellular 

 frond. 10 diam. 



2. Vaucheria Thiiretiiy Woronin : a, a, young antberidia ; a', antberidiiim which 



has discharged its autberozoi<ls; e, r, oogonia with oospores. 100 diam. 



3. PhyllUis faxcia, Kiitz; section of frond with plurilocular 8X)orangia, a, cover- 



ing the surface. 500 diam. 



4. Derbenia tenuinsima, (Do Not.) Crouan : a, spores (zoosporangia T) nearly mature ; 



6, 6', cross-partitions forming cell at base of sporangium. IW diam. 



5. Punctaria plantaginea, {llnth)Grcv.', transverse section of frond: a, plurilocnlar 



sporangia with zoosj)ores ; a', the same when oM, after the zoospores have 

 been discharged and the internal cell-walls obliterated. 



199 



