9(5 Clart — ffolophytic Plankton of Lairs AtitJan and Amatittan. 



in larger bodies of water. He is of the opinion that it forms an important 

 food supply of Entomostraca, 



Clathrocystis rpbusta is usually associated with Microcystis, Anabxna, 



and a few entomostraca. 



4. Gomphosphaeria aponia Kuetzing. 

 Gomphosphseria apon ia Kuetzing, Alg. ag. dulc. Dec. XVI, No. 151 ; 



Tab. Phyc. I, 22, Tab. 31, fig. Ill, 1845; Wolle, F. W. Alg. U. S., 328, 

 pi. CCX, figs. 20, 21, 22, 1887; Kirchner, in Eng. & Pr. Nat. Pfl-fam. 

 I, la, 50, fig. 49p, 1900. 



Frequently found mixed in with the Clatlirociisti^Microcijstis scum 

 mentioned above; sometimes present on the surface of the material, 

 usually alone in the form of small brown grains. All forms represented 

 the mature condition, and nearly all were bright yellowish brown in color. 

 Each cell usually exhibited a small dark speck resembling an eyespot. 



5. Merismopoedia glauca (Ebrenberg). 



Goniumt glaucum Ebrenberg, Infus., 58, pi. 3, f. V, 1838. 

 Merisiiiopwdia glauca Kuetzing, Tab. Phyc, Y. 13, Tab. 38. fig. 2, 1855; 



Wolle, F. W. Alg. U. S., 320, pi. CCX, figs. 12-15, 1887; Kirclmer in 



Eng. & Pr. Nat, Pfi-fam. I, la, 57, 1900. 



Rare. Only one specimen noted; this was in sample No. 1, "Amatitlan 

 in 85 ft, water, towed in about 75 to 05, February 1, 1900, at middle of upper 

 part of lake." It was associated with numerous other algse. 



Order OSCILLATORIACE.E. 

 6. Spirulina tenuissima Kuetzing. 



Spirulina tenuissima Kuetzing, Phyc. Germ., 150, 1845; Tab. Phyc, I, 20, 

 pl. 37, fig. IV, 1845; AVolle, F. W. Alg. U.S., 323, pi. CCX, fig. 3, 1887. 



One vial, marked "Jan. 24, dark colored alga' growing in very warm 

 water; left 30 hours, it turned red in bottle, put formal on it then; from 

 upper end of lake," contained a dark blue-green gelatinous stratum con- 

 sisting almost entirely of filaments of this species. A single filament was 

 also found in a flat gelatinous stratum composed mainly of Oscillaria 

 obtained from tbe surface, between pools of hot water, Laguna, January 

 13. Diameter of filament (diagonally, along axis of cells) 5/x, short axis 

 of cells 2/u, 



Tbe liquid in which the Spirulina was kept was of a beautiful amethyst 

 color. 



7. Oscillaria* cruenta Grunow. 



Oscillaria cruenta, Wolle, F. W. Alg. U. S., 312, pl. CCV1I, figs. 1-3 and 

 4-7, and pl. CCVI, fig. 5, 1887. 

 Abundant, forming a flat gelatinous striated stratum, brownish in 



•The name Oscillatoria is older than Oscillaria and covers a number of the species 

 included in the same genus. As I am unable to And what disposition has been made of 



these two spt-eies in the various revisions through which the group has passed, I leave 

 them under the familiar name Oscillaria. 



