116 ANIMAL FORMS 
Fig. 69 the mouth soon leads into the esophagus, which 
in turn leads into the crop that serves to store up the food 
until ready for its entry into the stomach; or in some of 
the ants, bees, and wasps it may contain material which 
may be disgorged and fed 
to the young. In many 
cases the stomach is small 
and ill-defined as in Fig. 69, 
and again it may reach 
enormous dimensions, near- 
ly filling the body. It may 
also bear numerous lobes or 
delicate hair-like processes, 
which afford a greater sur- 
face for the absorption of 
food. Behind the stomach 
are a number of slender 
outgrowths that are believed 
to act as kidneys. Beyond 
their insertion lies the in- 
testine, which, like the 
stomach, is the subject of 
Fig. 69.—Cockroach, dissected to show ali- many modifications in the 
oo al. c.—After HaTsELEK different kinds of insects. 
The digested food is rap- 
idly absorbed through the coats of the stomach and intes- 
tine and enters a circulatory system which reminds us of 
what exists in many of the Crustacea. The heart is situ- 
ated above the digestive tract, and from it arteries pass out 
to different parts of the body. Here the blood leaves the 
vessels and is poured directly into the spaces among the 
viscera, whence it is finally conducted through irregular 
channels to the heart by its pulsations. 
In the Crustacea the blood is made to pass through a 
respiratory system usually in the form of definite gills, and 
the oxygen with which it is charged is distributed to all 
