Mr. Brown took home some of these tubes in a collapsed state with the spider at the bottom. In one case, on opening the box in which the nest was placed, he perceived a movement throughout the tube, as if it were being inflated; this however soon subsided, but the following morning he was surprised to see that the whole tube was inflated, especially at the end which had lain exposed on the bank. He failed to find any aperture by which the spider could enter or leave her nest, and his captives, though passing backwards and forwards in their tubes, never came out at either end. He never saw flies or any fragments of insects in the nests; but, on drawing out one of the tubes, he observed a worm at the lower end, partially within it, partially outside, and he perceived that the spider had evidently been eating a considerable portion of its anterior extremity.
It will readily be seen that there are some discrepancies between the different accounts which have been given of the nests of Atypus found in England and France,[127] and I think it quite probable that some at least of the nests described may really differ, and be the work of distinct species belonging to this genus. Mr. Brown describes his nests as having by far the greater part of their length under ground, while in those observed by M. Simon, as shown in my figure, [Plate XIII] fig. A, the exposed portion of the tube equalled or exceeded the subterranean.
[127] A subject already alluded to in Ants and Spiders, at p. 78.
An imperfect specimen at the British Museum, from some English station (exact habitat not given), appears to have the proportions described by Mr. Brown; the length of the aërial portion of the tube being less than one-fourth of that of the subterranean; the upper end of the tube is however open, but I am doubtful whether this was originally so or not, for the silk is torn at this point, and the opening may be a rent caused by rough handling.
After a comparison of the above description, it appears to me that the following are the principal points which remain to be cleared up:
1. What is the precise structure of the nests of Atypus, and are they always uniform in character at all seasons of the year?
2. What is the use of the exposed aërial portion of the tube?
3. Do the two British species make similar nests?
4. What food, besides worms, does the female live upon, and how does she obtain it?
5. Does she ever leave the nest?