. Biology and man. Biology; Human beings. Compound eye Lens of ommatidium Perforated supporting membrane Retinal pigment Retinal cells Corneal lens Cone. Iris cells Lens- growing cells INSECT EYES The head of a locust showing the compound eye with its many facets, each repre- senting the exposed surface of an ommatidium, or single eye, and an ommatidium seen in section cut lengthwise. In the arthropods, or animals with jointed legs, there are compound eyes, as well as simple ones on the front of the head. The mouth, at the lower end of the head, con- sists of several distinct parts. The thorax
. Biology and man. Biology; Human beings. Compound eye Lens of ommatidium Perforated supporting membrane Retinal pigment Retinal cells Corneal lens Cone. Iris cells Lens- growing cells INSECT EYES The head of a locust showing the compound eye with its many facets, each repre- senting the exposed surface of an ommatidium, or single eye, and an ommatidium seen in section cut lengthwise. In the arthropods, or animals with jointed legs, there are compound eyes, as well as simple ones on the front of the head. The mouth, at the lower end of the head, con- sists of several distinct parts. The thorax, which is covered by the wings when the animal is at rest, is made up of three more or less distinct segments, or rings. Each segment carries one pair of jointed legs. Two of the segments carry one pair of wings each, and the anterior (forward) wings cover the posterior (hind) ones when at rest. The abdomen, like the thorax, is distinctly segmented. Indeed, the name of this class of animals. Insects, refers to the fact that the body is "cut in", or segmented, like the body of a caterpillar. This is easily observed in the abdomen of dragonfiies, bees, moths and beetles (see illustrations oppo- site). The foremost segment has on each side a small tympanum, or drum, which is actually an eardrum (see illustration opposite). The hindmost seg- ment bears special structures that have to do with the removal of refuse, other structures with reproduction. In the female these terminal parts to- gether constitute the egg-laying organ, or ovipositor. The bodies of insects and of mammals, like the bodies of plants, consist of many distinct parts or organs. And if we take the time to watch any ani- mals over a long period, we see that they too, like plants, undergo regular changes in form and in behavior. Comparing The moment we begin to compare carefully, we dis- cover that structures can correspond in many ways and yet not be the same, even if we call them by the same name. Thus
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Keywords: ., book, bookcentury1900, booksubjectbiology, booksubjecthumanbeings
