really fagged, for its onsets were at last much feebler than at first. I came away after twenty minutes, leaving the little hero in triumphant possession of his charge. Among some species of monkeys several individuals will join together in overturning a stone for the possible ants’ eggs under it; and, when a burying beetle has found a dead mouse or bird, it goes and gets its companions to help it in the interment.[3] Crows show benevolence by feeding their blind and helpless companions, and monkeys adopt the orphans of deceased members of their tribe. Brehm saw two crows feeding in a hollow tree a third crow which was wounded. They had evidently been doing this for some time, for the wound was several weeks old. Darwin tells of a blind pelican which was fed upon fishes, which were brought to it by its friends from a distance of thirty miles.[4] The devotion of cedar-birds to each other and their kindness to all birds in distress are well known to every student of ornithology. Olive Thorne Miller tells of a cedar-bird that raised a brood of young robins that had been left orphans by the accidental killing of the parents. Weddell saw more than once during his journey to Bolivia that when a herd of vicunas were closely pursued the strong males covered the retreat of the weaker and less swift members of the herd by lagging behind and protecting them.[3] A remarkable instance of altruism which he once saw exhibited by the king-crabs in a London aquarium is mentioned by Kropotkin in his work on ‘Mutual Aid a Factor in Evolution.’ One of these crabs had fallen on its back in a corner of the tank. And for one of these great creatures, with its saucepan carapace, to get on its back is, even in favourable circumstances, a serious matter. The seriousness was increased in this instance by an iron bar, which hindered the normal activities of the unfortunate crustacean. ‘Its comrades came to the rescue, and for one hour’s time I watched how they endeavoured to help their fellow-prisoner. They came two at once, pushed their friend from beneath, and after strenuous efforts succeeded in lifting it upright. But then the iron bar prevented them from achieving the work of rescue, and the crab again fell heavily on its back. After many attempts, one of the helpers went into the depth of the tank and brought two other crabs, who began with fresh forces the same pushing and lifting of their helpless comrade. We stayed in the aquarium for more than two hours, and, when leaving, came to cast a glance upon the tank. The work of attempted rescue still continued. Since I saw that I cannot refuse credit to the observation quoted by Dr. Erasmus Darwin that the common crab during the moulting season stations a sentinel, an unmolted or hard-shelled individual, to prevent marine enemies from injuring moulted individuals in their unprotected state.’ Walruses go to the defence of a wounded comrade when summoned by its cries for help.