. Animal physiology. Physiology, Comparative; Physiology, Comparative. Fig. 40.—Sandhopper. jointed members, the nervous ganglia are but little developed even in the head, and they all have nearly the same functions. Hence we might subdivide this group into two,—those which possess articulated members,— and those which are destitute of them. Each of these is again subdivided into classes. 103. In the highest division of the Articulated series, we easily recognise, as forms quite distinct from each other, the Insects, the Spiders, the Crustaceous animals (crabs, lobsters, &c), and the Centi
. Animal physiology. Physiology, Comparative; Physiology, Comparative. Fig. 40.—Sandhopper. jointed members, the nervous ganglia are but little developed even in the head, and they all have nearly the same functions. Hence we might subdivide this group into two,—those which possess articulated members,— and those which are destitute of them. Each of these is again subdivided into classes. 103. In the highest division of the Articulated series, we easily recognise, as forms quite distinct from each other, the Insects, the Spiders, the Crustaceous animals (crabs, lobsters, &c), and the Centipedes. The class of Insects is distinguished, for the most part, by the pre- sence of wings, but to this there are excep- tions. It includes those of the higher Articulata, which breathe air by means of air-tubes distri- buted through the body (§.320), which have no more than six legs, and whose body, in its perfect form at least, manifests a division into three distinct parts—the head, thorax, and abdomen (Fig. 41). To the thorax alone are attached the six legs, as well as the wings ; and its cavity is principally occupied by the muscles that move them : the abdomen contains the organs of digestion and reproduction, as in vertebrated animals. In the greater part of this class, the young animal comes forth from the egg, in a condition very different from that which it is ulti- mately to possess ; and it undergoes a series of changes, after the last of which only it presents the form of the perfect insect. In some tribes, the general form is the same from the first, and the wings. Fig. 41 Humble Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Carpenter, William Benjamin, 1813-1885. London : Wm. S. Orr and Co.
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