
REVIEWS. 37 
Handbook of Zodlogy (Leipzig, 1863). We might say, however, that the 
more conservative zodlogist would substitute class for sub-kingdom, and 
order for class, considering the worms as a class of the “ type,” “ branch,” 
or “‘sub-kingdom” ARTICULATA. Such tabular lists of different classes of 
the animal kingdom we design to give from time to time in the NATURAL- 
Ist. The Rotifera, or Wheel-animalcules, placed by Dana and other au- 
has been aonr by Dugés, who, by slicing them with scissors, produced 
individuals with double heads and tails, and sioa modifications of form. 
The curious modes of reproduction are thus n 
The Turbellarians propagate either by eggs deposited and fertilized in the water, several 
eggs being often de ted in one mass of yolk (like what was observed by Dr. Carpenter in 
grow A 
in a larva gages which is ped unlike R ‘parent, and from me DONS SY which a 

last case is very nenas to that observed by Johannes Mueller in Sites star-fishes, As int 
Echinoderms, so in n the Turbellarians,. there a appears to be no rule a me method of Jeren 
opment; nearly di liti 
a larval st: ‘ni and th 
Dr. Richardson writes on ‘the Physics of the Brain, A concludes 

J E 
+} a 3 

or ganglia are determined, ‘‘that impressions are physical realities, 
stamped as it were on brain matter, each distinct and perfect when 
the matter on which it is set is in condition for motion. Everything 
we remember is, I doubt not, thus imprinted on the brain, on infinite 
points of brain-substance, each ee fre, a capable of motion 
when the whole mass is charged with fi The ' brain, in fact, is a 
world within of the world without that it par received in the course of 
its waking life.” 
When we see what the micro-photographer can thus do in putting physical Te 
on what seem infinite: tesimal points of matter, and when we know that there is no as 
limit to this art, it i e of the gray matter ree bai 
Inos cerebral lobes or which Tave spoken, mpenes ‘ot points i matter are thus 
” 



up. 
One more fact relating to the physics of the brain, as taught by experiment, and I have 
done. We have seen that when the anterior cerebral ganglia are destroyed for a time, an 
À d he bell 
rward, hat, m the cere the 
moves impulsively backwards. indicates the existence of a balance of power between 
t ; a balance which is also detectable between other centres. It 
ery centre of power in the brain is, during healthy states, 

