116 



THE AMERICAN MONTHLY 



9m 



[June, ■ 



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, Duj. {Trachelius 

 tricophorus, Ehr.) Body colorless, 

 very metabolic, constant in shaj)e 

 or changing very gradually, swims 



{generally slowly, and in a straight 

 ine. 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. 



A. hcemotodes, Ehr., red, and ^. 

 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 tlie head, at the posterior border 

 of which 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. 0.04r-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 

 ProtOGoecus, 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 algae, not common. 



E. aous, Elir. Body long, spindle- 

 shaped, form constant, only occa- 

 sionally slowly contracting. L. 0.1. 



E. sjpirogyra, Ehr. Body spirally 

 marked, with two very large, ring- 

 like nuclei. Color green or brown- 

 ish. L. 0.2. Singly, among algae. 



4. Gen. Anfibliojyhis, 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. viridis, Ehr. Green; 1. 0.02 

 in stagnant water not common. 



5. Gen. Chlorogonium, Ehr. 3odj 

 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 



