made during the out-going journey, and that this power of registration has reference only to lateral movements; it has no reference to variations in the velocity of advance along the line in which the animal is progressing.
Powers of Communication.—Huber, Forel, Kirby and Spence, Dujardin, Burmeister, Franklin, and other observers have all expressed themselves as holding the opinion that ants are able to communicate information to one another by some system of language or signs. The facts, however, on which the opinion of these earlier observers rested, have not been stated with that degree of caution and detail which the acceptance of their opinion would require. But the more recent observations of Bates, Belt, Moggridge, Hague, Lincecum, McCook, and Lubbock, leave no doubt upon the subject. Two or three instances will be enough to select in order to prove the general fact. Hague, the geologist, kept upon his mantel-shelf a vase of flowers, and he noticed a file of small red ants on the wall above the shelf passing upward and downward between the latter and a small hole near the ceiling. The ants, whose object was to get at the flowers, were at first few; but they increased in number during several successive days, until an unbroken succession was formed all the way down the wall. To get rid of the ants, Hague then tried frequently brushing them off the wall upon the floor in great numbers; but the only result was that another train was formed to the flowers ascending from the floor. He, therefore, took more severe measures, and struck the end of his finger lightly upon the descending train near the flower-vase, so killing some and disabling others. "The effect of this was immediate and unexpected. As soon as those ants which were approaching arrived near to where their fellows lay dead and suffering, they turned and fled with all possible haste, and in half an hour the wall above the mantel-shelf was cleared of ants." The stream from below continued to ascend for an hour or two, the ants advancing "hesitatingly just to the edge of the shelf, when, extending their antennæ and stretching their necks, they seemed to peep cautiously over the edge until beholding their suffering companions, when they too turned, expressing by their behavior great excitement and terror." Both columns of ants thus entirely disappeared. For several days there was a complete absence of ants: then a few began to reappear; "but, instead of visiting the vase which had been the scene of the disaster, they avoided it altogether," and made for another vessel containing flowers at the other end of the shelf. Hague here repeated the same experiment, with exactly the same result. After this for several days no ants reappeared; and during the next three months it was only when fresh and particularly fragrant flowers were put into the vases that a few of the more daring ants ventured to straggle toward them. Hague concludes his letter to Mr. Darwin, in which these observations are contained, by saying: