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 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. [Illustration: FIG. 24.—_Eudoxia._ (After Chun.)] [Illustration: FIG. 25.—_Botryllus_ colonies. _o_, mouth ; _A_, common cloaca.] 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.