JULY — SEPT. 1857.] The Vohox Glolalor. GOT 
spontaneous motion or more properly locomotion. But this was 
soon seen to be insufRricnt for most of the Polypes and some of 
tlie Echinodermata ; all Cirripedes ; and even some of the higher 
orders — ihe Serjmla among Articulata. and the Oyster among 
Molluscs are fixed to the rocks on which they grow. 
On the otlierhand the Spores of many Algce is of Vaucheria and 
of the Sponges have a very rapid locomotion. 
The next distinction attempted to be drawn was taken from the 
mode of deriving nourishment, " plants''' it was said "absorbing 
" nutriment by means of fibres at the lower extremity of the bod}', 
" animals by afi opening (or mouth) at the upper end, conducting 
" to a capacious sac" (or stomach.) 
But the Gregarina, a genus of microscopic parasites infesting 
gregariously the intestinal canals of insects, worms, Sec. and seve- 
ral of the free iNrusouiA have neither mouth nor stomach and 
there is no stomach in Cestoidea one of the larger Entozoa. They 
are supposed to derive nutriment by absorption through the skin. 
A third characteristic was supposed to have been found in the fa- 
culty possessed by plants of exhaling oxygen whilst animals expire 
carbonic acid. But"here too the distinction fails : some of the free 
moving Polygastria eliminate pure oxygen in one stage of their 
existence while Mushrooyns and Sponges have been found to give 
out pure carbonic acid gas. 
Another chemical distinction it was thought had been discover- 
ed in the quaternary composition of animals which are resolvable 
into carbon, oxygen, hydrogen and nitrogen, whereas owing to the 
absence of the last mentioned element, the constitution of plants 
is ternary. Celhdose indeed is a binary compound of carbon and 
hydrogen only. But neither does this definition hold. Nitrogen 
is found in Algce, Fungi and most cryptogamous plants. And on 
the other hand, the mantle of Frustulia a mouthless Folygastria 
and the thick cellular coat of Astidia are binary compounds. Mr. 
Bidie has shown that there is reason to suppose the same binary 
constitution is net unknown among the highest order of animal ex- 
istence, in the brain of Mammalia. 
