Page:The Zoologist, 4th series, vol 5 (1901).djvu/352

324 the rods of a crab-pot, enter the opening, descend within, mount again to the situation of the bait, and select the particular one that pleases it best." The homing habits of the Common Limpet (Patella vulgata) have been ascribed to the possession of a "locality sense."

Nearly all writers and investigators have felt the difficulty in properly describing the sensory impressions of animal life. According to Prince Kropotkin:—"We must be prepared to find that the usual division of senses into touch, taste, smell, vision, and hearing will not do for the whole series. The senses must be rather divided into a mechanical, chemical, temperature, and light sense, to which the electrical sense will perhaps have to be added. Such a division undoubtedly better answers to the senses which exist in the lower animals, and when the series is considered in an ascending order, the gradual differentiation of the chemical sense into taste and smell, and of the mechanical sense into touch, hearing, and pressure sense, becomes evident." Brehm states that careful observations on the habits of Mosquitos "places it beyond doubt that in the discovery of their victim they are guided less by sight than by smell, or perhaps, more correctly, by a sense which unites smell and tactile sensitiveness; while Mr. J.A. Thomson, in an editorial note, remarks: "The somewhat mysterious reference which Brehm makes to a sense between smell and touch is thoroughly justifiable. To the senses of many of the lower animals—and even of fishes—it is exceedingly difficult to apply our fairly definite human conceptions of smell, taste, touch, &c." The restlessness or alarm shown by birds or other animals before the occurrence of an earthquake sensible to man is well known, and is probably due to the very small tremors which precede the larger vibrations. Dr. Alexander Hill has recently sympathetically approached this subject, and we give one extract in his own words:—"If we try to figure to ourselves the mental activities of any animal, we