890 EVENINGS AT THE MICROSCOPE. 



assuming an appearance very diverse from what it had half 

 a minute before, so that you would hardly identify it, if 

 you were not watching its evolutions. Whether this ability 

 to prove an alias be at all dependent on the remarkable 

 clear-headedness of the subject, I leave for those who are 

 skilled in metaphysics to determine. Away they go, 

 tumbling over and over, revolving on the long axis as they 

 proceed, which they do not very rapidly, with the blunt 

 extremity forward. 



Here -is another form, a little larger than the former, 

 but much more slender ; yet from the slowness and steadi- 

 ness of its movement more easy of observation. It is 

 named E. acus, or "the Needle Euglena." This is an 

 animalcule of great elegance and brilliancy ; its sparkling 

 green hue, with colourless extremities, and its rich pale 

 ciimson eye, are very beautiful. It commonly swims ex- 

 tended, with a slow gliding motion, turning round on its 

 long axis as it proceeds, as may be distinctly seen by the 

 rotation of certain clear oblong substances in its body. 

 These, then, are seen not in the interior, but near the 

 surface, as they would appear if imbedded in the flesh 

 around a hollow centre. The interior is probably not 

 hollow, but occupied with pellucid sarcode. These were 

 assumed by Ehrenberg, but on no adequate grounds, to 

 be organs connected with reproduction. They vary in 

 number in different individuals, and those which contain 

 the greatest number are thereby more swollen. They 

 appear to be separated into two series, one anterior, the 

 other posterior. The animal is capable of bending its 

 head and body in various directions, but is most beautiful 

 when straight. The front is furnished with a slender 

 thread-like proboscis. This species affords us a good 

 opportunity of observing the red spot, which, for con- 

 venience sake, we may still term an eye. It seems to be 

 an irregular oblong vacuole, or excavation in the sarcode, 

 filled with a clear ruby-red fluid. The red spot in the 



