116 



THE AMERICAN MONTHLY 



[June, 



Individuals moving free, with 



one flagellum in front, this with a 



large base, from the pear shaped, pointed 



end ; no stigma, 

 slender base, from the blunt or emarginate end, the latter 

 without a stigma, 

 • with a stigma 



body pointed behind, 

 body blunt behind, 

 two flagella in front 

 both alike 



on the pointed end of the body, 

 on an emarginate part of the body, 

 dissimilar, one moving one trailing, 

 Individuals with the pointed posterior end fixed, often in families, 



Peranema. 

 Astasia. 



Euglena. 



Amblyophis. 



Chlorogonium. 



Zygoselmis. 



Dinema. 



Colacium. 



1. Gen. Peranema^ Duj. Shaped 

 like a long pear, the small end 

 continued into the moving flagel- 

 lum ; at the base of the latter an 

 oblique mouth opening, below this 

 a vesicle. 



P. protracta^ I^u.j. {Traclieliiis 

 tricophorus, Ehr.) Body colorless, 

 very metabolic, constant in shape 

 or changing very gradually, swims 

 generally slowly, and in a straight 

 line. 0.03-0.07. Common in de- 

 tritus, but single. 



P. glohosa and P. verescens^ Duj. 

 Appear not to be generically differ- 

 ent. 



2. Gen. Astasia, Ehr, Body elon- 

 gated, emarginate in front without 

 stigma. 



jL. hce7notodes, Ehr., red, and A. 

 viridis, Ehr. Green, 0.06 1. Ap- 

 parently these belong to the follow- 

 ing genus. 



3. Gen. Euglena^ Ehr. Body fish- 

 shaped, green, with a hyaline place 

 in the head, at the posterior border 

 of w^hich is the red pigment spot. 

 In place of the mouth there is a 

 slight swelling from which the fla- 

 gellum arises (which, however, 

 often is not present, or is invisible). 

 In the central part of the body are 

 rounded or oval chlorophyll granules. 



E. viridis, Ehr. Body green, 

 metabolic, only constant in shape 

 while swimming ; turning in a long 

 spiral as it swims. L. 0.04—0.08. 

 Common in all stagnant water, very 



abundant in bad-smelling puddles 

 and ditches, the grass-green coat- 

 ings of which are often made up 

 of Euglense. Division follows an 

 encysting process. The cysts which 

 are hardly to be distinguished from 

 ProtococGus, often are so close to- 

 gether so as to form an ulva-like 

 scum in which they appear as six- 

 sided masses. 



E. sanguinia^ Ehr. Only differs 

 from the former in color, and seems 

 to be the winter-form of the same. 



E. deses, Ehr. Body elongated, 

 0.07-0.11. Movement crawling, 

 never swimming, but slowly wind- 

 ing. Among algse, not common. 



E. acas, Ehr. Body long, spindle- 

 shaped, form constant, only occa- 

 sionally slowly contracting. L. 0.1. 



E. spirogyra, Ehr. Body spirally 

 marked, with two very large, ring- 

 like nuclei. Color green or brown- 

 ish. L. 0.2. Singly, among algse. 



4. Gen. Ambliophis, Ehr. Body 

 large, similar to the preceding, but 

 blunt behind, with a large vacuole 

 in the middle, in front and behind 

 which are several rod-like nuclei. 



E. mridis, Ehr. Green ; 1. 0.02 

 in stagnant water not common. 



5. Gen, Chlorogoniu7n,Eh.r. Body 

 spindle-shaped, stiff, not contractile, 

 with two flagella on one of the 

 pointed ends, and a pigment spot 

 near by. The genus differs from 

 the preceding forms not only in the 

 want of contractility, but also in 



