50 SPECIES OF ALG^E. 



35. EUGLENA. 



The question as to the animal or vegetal character of Euglena has 

 been debated. The present tendency is to consider it an alga, 

 although the evidence is rather negative than positive. For the 

 present purpose however, it seems best to leave- it among the Infu- 

 soria, where the older investigators classed it. 



36. GONIUM. 

 One species pectorah, 163 



37. STEPHANOSPH^ERA. 



No forms yet found in this country. 



38. CHLAMYDOCOCCUS. 



a. Cells subglobose, brownish-red, sometimes green; variable, 



pluvialis, 1 64 



a. Cells globose, red; at first with a hyaline border; on the snow of 

 high peaks, etc nivalis, 166 



39. CHLAMYDOMONAS. 



With a red pigment spot (a). 

 Without " " " (b). 



a. Ovate; length twice the width; pigment spot lateral, 



pluviusculuSj 1 6 8 



b. Pale, whitish green; oblong-elliptical . . . . . hyalina, 168 



b. Bright light-green (c). 



c. Ovate or oval tingens, 167 



c. Spherical or nearly so pluviale, 167 



40. PEDIASTRUM. 



For full descriptions and figures of the species, see Wolle's "Des- 

 mids of the United States," from which the following classification is 

 compiled. 



Apices cuspidate, each cell with one cusp or bristle (a). 

 " " " " " two " " " (c). 



Apices or angles, bidentate; small; cells often 4 . cuspidatum, 154 

 Apices truncate; cells 4 in form of cross, 4-sided; small, tetras, 154 

 Apices concave, undulate (d). 

 Apices bilobed (<?). 



a. Cells six, ovate or subfusiform, radiately connected; centre closed, 



simplex, 152 



a. Cells six, 5 angled; centre open Sturmii, 153 



a. Cells more than six (b). 



