INTRODUCTION. XXVil 
animal, upon being wounded in either of the limbs, would 
of necessity bleed to death. That such would be the case 
would appear to be extremely probable, but, like all nega- 
tive evidence, is only of value in the absence of direct 
testimony. In the Sessile-eyed orders the animal appears 
to want the power of voluntarily throwing off any of its 
appendages, no matter how severely it may be wounded. 
If a leg be cut off, or in any way injured, the wound 
very soon after becomes cicatrized with a black scar, 
which remains until the next exuviation of the animal, 
when the entire limb is thrown off with it, and a new one 
commences growing. 
TasTE AND DIGESTION. 
The sense of the enjoyment of food, even in the highest 
types of the animal kingdom, exists rather in the power 
of parts to receive impressions than in the presence of 
any especial organ for the purpose. Arguing, therefore, 
from analogy, we should suppose that the sensation of 
taste in the lower animals (such as the Crustacea, and 
other groups in which mastication is of an imperfect 
character), must necessarily be rather a faculty peculiar 
to the mouth in general, than the result of any especial 
organ adapted for the purpose. 
From the mouth the cesophagus leads directly to the 
stomach. The passage is very short, being directed up- 
wards and forwards; it enters the stomach at the infero- 
anterior margin, and, as in all Crustacea, is within the 
limit of the cephalic region. 
Just within the anterior opening of the stomach are 
situated two rake-like organs, the teeth being placed in 
a row on an arched base; they are slightly curved and 
dentated on the margins. They are so placed as to have 
