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In support of my view, I must recall the small forms of Siphonophora known as Eudoxia. These are detached pieces of the common trunk which swim freely in the sea and have a remarkable structure (Fig. 24). Their mobility is due to a bell provided with strong muscular fibres. The bell is a portion of an individual which possesses organs of reproduction but which is devoid of the means to capture or digest food. These two functions are performed by a second individual which is closely united with the first. The nutrient individual has a long

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tentacle by which the prey is captured, and a capacious stomach in which it is digested. The products of digestion pass by channels into the reproductive individual, carrying as it were a ready-made blood. Eudoxia in fact is a double being composed of an individual incapable of locomotion or of reproduction, but adapted for prehension and digestion, and of a second individual which can reproduce and which is mobile. Eudoxia is an association resembling that of the blind man and the paralytic, in Florian's fable.

Advance in the organisation of social animals is plainly

incompatible with complete loss of individuality, and this becomes the more apparent the higher we reach in the scale of life. In the social Ascidians, each member retains all the organs necessary to life. Animals of the genus Botryllus (Fig. 25), perhaps the most interesting of these Ascidians, occur in the form of circular colonies. The individuals which compose the colony are grouped radially around a common centre which is occupied by the cloaca. Each individual has its own mouth and digestive tube, but the latter opens into a cloaca, common to all the individuals, by which the excreta are voided. There is, in fact, a single anus, as in the case of Rosa and Josepha which I have just mentioned.

II

INSECT SOCIETIES

Social life of insects-Development and preservation of individuality in colonies of insects-Division of labour and sacrifice of individuality in some insects

HITHERTO I have dealt with associations of animals the members of which are linked by an actual material bond. In the insect world there are many cases of highly developed colonies. But the organisation of insects is high, and is incompatible with the existence of actual physical connection between the members of the society.

In early stages of the development of the social instinct in bees, fully formed and similar individuals join together with the object of securing the safety of their individual lives. Sometimes they act together to drive away a common enemy, sometimes, as in winter, they cling in a mass to maintain their temperature. In such primitive societies, the young are not reared in common. It is only in much more highly developed colonies, such as those of some bees and wasps, and of ants and termites, that the chief object of the common action is care of the progeny. Such an extreme development of the colony is attained only by sacrificing the individuality of the members. There is a far-reaching division of labour, so that the queens, for instance, are mere machines for laying eggs. In hive-bees

the queen can no longer judge of what is good for the colony, her intellectual functions being degenerate. She is enclosed in her cell and supported by the workers, who see in her the future of the race. In times of want the worker-bees sacrifice their own lives and give the queen the last remnants of the food-supply so that she survives them. The males are incomplete individuals and are tolerated only so long as they are required, after which the workers kill them remorselessly.

The workers, which take such pains for the well-being of the hive, are incomplete individuals. Their brains are well developed and they are well equipped with organs for making wax and collecting food, but their reproductive organs are reduced to mere vestiges incapable of fulfilling their functions.

Here then is a case of loss of individual characters increasing with the perfection of the colony. Amongst ants and termites, the social life of which arose quite independently of that of bees, the same course of events has been repeated. High intelligence and skill are confined to the workers, in which the reproductive organs are atrophied. The soldiers have powerful jaws used in defence of the camp, but they, too, are sexually incomplete. The females and males, in which the reproductive organs have attained huge proportions so that the bodies are little more than sacs containing the sexual elements, have no intelligence and very little skill.

An extremely curious specialisation, consisting in the formation of honey-bearing workers, occurs in some Mexican ants. Some of the workers of these races absorb so much honey that their bodies become swollen honey-bags. The limbs can no longer support the expanded body, and the insects, reduced to immobility, do not quit the burrows.

Normal life has become impossible for these individuals, who soon die for the good of the community. When the normal workers or the sexual individuals are hungry, they approach the honey-bearers and take honey from their mouths. The honey-bearers have be

ant.

(After Brehm.)

come no more than animated cupboards (Fig. 26).

The termites belong to quite another FIG. 26.—A Honey- class of the group Insecta, but in their case a similar sacrifice of the individual to the state is practised. The females become transformed to shapeless bags of eggs. They cannot move, but remain secluded in the recesses of the "ant "-hill, where they lay as many as 80,000 eggs a day. The soldiers have become provided with jaws so enormous that these unsexed insects can perform no function other than defence of the colony.

The partial reduction of individuality in social insects never goes so far as in the cases of the lower animals I have described. It may be stated as a general rule that increase in the perfection of organisation brings with it a more or less complete preservation of individuality in the members of a community.

I shall now examine to what extent this law can be applied in the case of man.

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