146 PHOTO-MICROGRAPHS. 
We have been obliged to concede that it may 
be endowed with the capacity and the apparatus 
(flagella) for active locomotion; but a plant with a 
mouth would be too great a tax upon our imagina- 
tion, notwithstanding the fact that the creature 
contains chlorophyl and starchlike granules. 
In allowing, however, to Euglena the rank to 
which its microscopic mouth entitles it, we must 
not forget that the distinction between plants and 
animals is not sharply drawn among these lowly 
organisms, and that the lines drawn by natural- 
ists in their attempts to classify the living forms 
that come under their observation, are to a great 
extent arbitrary and artificial. Nature is con- 
tinuous; but the links in the chain were not all 
forged at one time, nor is it possible for the most 
industrious naturalist carefully to study all the 
forms existing to-day. Consequently, breaks occur 
in his chain; and these are erected into generic 
and specific barriers, which are constantly being 
changed as new discoveries are made. 
Our photo-micrograph of Luglena viridis shows 
the form of the creature when at rest, but does 
not show its green color, its red “ eye-speck,” or 
its flagellum, which is not always present. 
Extended green patches are frequently seen 
upon the surface of the moist mud along the mar- 
gins of the open gutters of New Orleans, which 
upon examination with the microscope are found 
to be made up of these little creatures. When 
at rest, they resemble so closely the unicellular 
Algee that it is hard to convince oneself that they 
