. The Cambridge natural history. Zoology. CHAP. XHI ARANEAE—SPIDERS 315 and the mmiber of known forms is certain to be very largely increased. They form an extremely compact and natural group, for though, within the order, there is an infinite variety of detail, their rmiformity in essential points of structure is remark- able, and they are sharply marked off from the neighbouring of Arachnida. It is perhaps unfortunate that the obtrusiveness of particularly unattractive specimens of the race has always caused spiders to be regarded with more or less aversion. This prejudice can hardly
. The Cambridge natural history. Zoology. CHAP. XHI ARANEAE—SPIDERS 315 and the mmiber of known forms is certain to be very largely increased. They form an extremely compact and natural group, for though, within the order, there is an infinite variety of detail, their rmiformity in essential points of structure is remark- able, and they are sharply marked off from the neighbouring of Arachnida. It is perhaps unfortunate that the obtrusiveness of particularly unattractive specimens of the race has always caused spiders to be regarded with more or less aversion. This prejudice can hardly fail to be modified by a wider acquaintance with these animals. There are certainly few groups which ' present points of greater interest in respect to their adaptation to special modes of life and the ingenuity displayed in the con- struction of their nests and the en- snaring of their prey. Spiders are wingless, yet they may often be observed travelling through the air. They are air-breathing, yet many are amphibious in their habits, fig. 172.—Epeira anguiata. 9. and one species at least spends the greater part of its existence beneath the surface of the water. On land they may be found in all imaginable localities which admit of the existence of that insect life on which they depend for food. External Structure.—The spider's body consists of two portions, the cephalothorax and the abdomen. Cephalothorax.—Looked at dorsally (Fig. 173), the cephalo- thorax is generally seen to have a depression near the middle, the " median fovea," and from this certain lines, the " radial striae," radiate towards the sides. These depressions indicate the attach- ment of internal muscles. The head region or " caput " lies in front of the foremost of the radial striae, and is often clearly marked off from the thorax, and different from it in elevation. It bears the eyes, which, in the great majority of spiders, are eight in number. Many, how- ever, are six
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