in the form of 2 thick rods, one anterior and one posterior to the 

 central nucleus; cells 7-10^1* in diameter, (60)-70-80/x long. 



Widely distributed in Sphagnum bogs and ditches, but sparse in 

 occurrence. Wis. 



PHACUS Dujardin 1841, p. 334 



Cells ovate, pyriform, fusiform, or orbicular, often twisted or in 

 part spiral, and much flattened, with a long or short caudus in most 

 species; a gullet in the anterior end marked by a fold in the mem- 

 brane; 1 fiagellum arising anteriorly, sometimes through an apical 

 papilla; periplast decorated with longitudinal or spiral striations, 

 rows of granules, or punctations; chloroplasts numerous ovoid discs, 

 rarely bands; paramylon bodies in the form of circular plates or 

 rings, rarely rods; pigment-spot usually present, placed laterally at 

 end; cells never metabolic as in Euglena. 



Key to the Species 



1. Caudus (tail-piece) lacking; cells broadly 



rounded posteriorly — P. Segretii 



1. Caudus present, straight or curved - 2 



2. Periplast with longitudinal or spiral rows of 



granules or sharp warts 3 



2. Periplast longitudinally or spirally striated, or smooth 4 



3. Cells pyriform; granules in longitudinal rows P. suecicus 



3. Cells ovate or fusiform; granules in spiral rows -P. Spirogijra 



4. Cells distinctly pyriform - 5 



4. Cells globose, subglobose, ovoid-fusiform, or ovoid 7 



5. Chloroplasts several longitudinal bands P. chloroplastes 



5. Chloroplasts circular or ovoid discs , 6 



6. Protoplast inclosed by a spirally striated periplast 



from which it is remotely separated - - P. Nordstedtii 



6. Protoplast not separated from the periplast P. pijrtnn 



7. Cells (70)-80-190xlong, with a long caudus nearly 



or quite as long as the cell body - 8 



7. Cells mostly shorter; caudus much shorter than the cell body 10 



8. Cell body flat, ovoid, or nearly round in outline, with a 

 straight or nearly straight caudus as long as 



or longer than the cell body P. longicauda 



8. Cells strongly twisted, fusiform in outline - 9 



9. Cells twisted throughout their length P. helikoides 



9. Cells twisted only in the caudal portion P. tortus 



10. Cell with a short, straight, almost papilla-like caudus P. acuminatum 



10. Cell with a conspicuous caudus, straight, 



curved, or strongly reHexed 11 



11. Cell with evenly undulate margins ___ P. crenulata 



11. Cell with margin entire, irregularly undulate, 



or notched unsymmetrically— 1 2 



12. Cell unsymmetrically fusiform, somewhat euglenoid - P. asymmetrica 



12. Cell ovoid or orbicular in outline, symmetrical or nearly so 13 



[395] 



