SPECIES OF ALG^E. 55 



62. RHAPHIDIUM. 



a. Cells straight or nearly so, length 15-20 times the diameter, 



aciculare, 197 



a. " " " " " " 20-30 or more times the diameter, 



contortum, 198 



a. Cells decidedly curved; often crescentic or sigmoid (b). 



b. Cells sigmoid, single or 2-4 connected .... sigmoideum, 198 



b. Cells more or less crescentic (c). 



c. Cells connected back to back, crescentic, sometimes single, 



convolutu m, 198 



c. Cells not connected, long, slender, falcatum, 198 



c. " " " short, thick, diameter 5-7 /* . Braunii, 198 



63. DIMORPHOCOCCUS. 



One species cordatus^ 199 



64. MISCHOCOCCUS. 



One species confervicola, 200 



65. EREMOSPH^RA. 



One species viridis, 200 



66. UROCOCCUS. 



a. Stem densely ringed, often divided .... Hookerianus^ 201 

 a. Stem short, remotely annulated insignis, 201 



67. APIOCYSTIS. 



One species Brauniana, 202 



68. CHYTRIDIUM. 



. On the oogonia of various CEdogonia; cells somewhat urn-shaped, 

 with a lid acuminatum, 202 



a. On various filamentous Algae (b). 



b. With a low lid; pale yellow minus, 203 



b. Without a lid; cells spherical ...*... globosum, 203 



69. OLPIDIUM. 

 On the exterior of the host; cells globose; mouth cylindrical, 



nearly as long as the cell ampullaceum, 203 



In the interior of the host; perforating neck tubular, middle 



globosely dilated intestinum, 203 



In the interior; perforating neck straight, not inflated, 



entophytum^ 204 



