Geology and Natural History. 151 
of Chlorococcus has 
surface of a liquid, 
name of Huglena; a third, ormin 
slime upon old walls, 
fth, Vaucheria ; a sixth, Sehid- 
rie products, and a study of their life-history, leads to 
some a that they are all (more or less) stag 
“a "te common source, which it is the object of the present 
Which ha; ss as the monad, or pin-point, source of life, 
Test ag .been pointed out by Dr. Bastian and others as the ear- 
Test. which we recognize living matter. : 
bservati r to commence this investigation I will append a few 
‘vations I have made on various forms of Paramecium, and 
A deayor to show that it constantly transforms to Vorticella, 
0 passes to Callidina elegans, thus tracing 
Some ¢ growth by development from the simp 
me of the more complicated animaleule or Entomostraca. 
