56 Elementary Munuat of Zoology. 
nearly all the saddles belonging to the Debra Dun 
volunteers. A plentiful use of spirits of turpentine upon 
woollen material that is put away is about the simplest 
way of preserving it from attack, but the insect is a very 
difficult one to eradicate. 
(4) The students should also notice the fact that microlepi- 
dopterous caterpillars belonging to various species bore 
into mangoes, pomeloes, and other fruits, also into the 
stalks of sugarcane, sorghum, rice, and wheat, besides 
injuring agricultural plants in other ways. They should 
also examine the specimens of Microlepideptera in the 
School Museum and make a sketch of a branch attacked 
by the toon-borer, 
(5).—CHorDATA. 
This group may be defined as comprising bilaterally symmetrical 
ccelomate animals, which have the body supported by an internal median 
rod (notochord), which separates the main nerve system from the diges- 
tive organs. It comprises the Urochorda, the Cephalochorda, the 
Cyclostomi, and the Vertebrata, 
(2) Urochorda.—This group comprises the Acidians and allied 
animals, which have the notochord confined to the tail and 
usually present only in larval life, They are degenerate 
sea-living animals of small size and are of no practical 
importance tothe forester, though they should be noticed, 
as they are to some extent intermediate in structure 
between the Vertebrata and the lower groups of Celomata. 
They breathe water by means of gill-slits, which per- 
forate the pharynx, as in the higher water-breathing mem- 
bers of the Chordata, while the arrangement of the nervous 
system in the larva is essentially similar to that of the 
higher forms. The adult animals are degenerate, usually 
stationary, barrel-shaped organisms. They have the body 
enclosed in a curious case, whence has arisen the name 
Tunieata, by which the group is often known. 
(2) Cephalochorda.—This group comprises the Amphiovus, which 
is a small fish-like animal about a couple of inches long, 
found in shallow seas (¢.g., some parts of the Bay of 
Bengal). It is of no practical importance to the forester, 
but should be carefully noticed, as it very nearly represents 
what is believed to be the primitive ancestral form of the 
vertebrata. The group may be defined as Chordata with 
notochord persistent throughout life, but without skull, 
lower jaw, or paired limbs, Both in structure and in 
