ACEPHALA.

SUB-KINGDOM ARTHROPODA (Insects, Spiders, Centipedes, Crabs, etc.).

Class Insecta (beetles, bugs, butterflies, etc.).—Animals whose bodies are made up of segments grouped together in three regions, the head, thorax, and abdomen; having three pairs of jointed legs, and one or two pairs of wings, and breathing air through openings in the sides of the body. The word insecta comes from a Latin word, inseco, I cut into, referring to the distinct separation of the body into regions.

INSECTS.

Class Myriapoda (centipedes, millepedes). Animals composed of many segments. These not apparently combined into regions, except the head, which is distinct. The number of pairs of legs coinciding with the number of segments. Breathing air through openings in the sides of the body.

The word myriapoda is derived from two Greek words, murioi, ten thousand, and pous, foot.

A MYRIAFOD.

Class Arachnida (spiders). Animals whose bodies are segmented. The segments grouped together into two regions, the cephalo-thorax and the abdomen. Having four pairs of legs, and breathing air through openings in the body.

The word arachnida is derived from a Greek word, arachne, spider.

3

ARACHNIDS.

Class Crustacea (lobsters, crabs, barnacles, etc.). Difficult to define, but including animals which pass through a series

of moults in their growth, though in this respect resembling the spiders, and breathing by means of gills, and in this respect differing from other arthropods.

CRUSTACEANS.

SUB-KINGDOM VERMES (worms). Class Annelida (angleworms, leeches, certain sea-worms, etc.). Animals whose bodies are made up of an indefinite number of segments, bearing appendages which are not jointed, and in the larger number of groups having bunches of bristles or setæ upon the sides of the body which act as supplementary organs of locomotion. The name annelida is derived from the Latin word annulus, a ring.

WORMS.

SUB-KINGDOM VERTEBRATA, with the following classes, which have been only briefly alluded to: Fishes, Amphibians, Reptiles, Birds, Mammais. According to a late classification of Professor Huxley's, these classes would stand Ichthyopsida, which includes the Fishes and Amphibians; Sau