Page:Wood 1865 - The Myriapoda of North America.djvu/2

 THE MYRIAPODA OF NORTH AMERICA.

BY H. C. WOOD, JR., M.D.

Read June 16, 1865.

Myriapoda are air-breathing apterous articulata characterized by the distinctness of the head from the body; the strongly marked segmentation of the latter, and its method of development.

The head varies very much in size and the perfection of its organization, but is always separate and distinct. The organs of special sense are very well developed in all but the lowest orders. The eyes are in one family compound, in the others stemmatous and single or numerous, or else entirely wanting.

The body is composed of a varying number of segments, most of which are merely a repetition of the preceding. The number varies from sixteen to several hundred. As a general rule, the fewer the segments the higher the organization. Each perfected segment is formed from two subsegments, either by their coalescence and mutual growth, or