In the phylactolæmata the life-history is much better known, having been studied by several authors, notably by Allman, by Kraepelin, and by Braem (1908). The egg is contained in a thin membrane, and while still enclosed in the zooecium, forms by regular division a hollow sphere composed of similar cells. This sphere then assumes an ovoid form, becomes covered with cilia externally, and breaks its way through the egg-membrane into the cavity of the zooecium. Inside the embryo, by a process analogous to budding, a polypide or a pair of polypides is formed. Meanwhile the embryo has become distinctly pear-shaped, the polypide or polypides being situated at its narrow end, in which a pore makes its appearance. The walls are hollow in the region occupied by the polypide, the cavity contained in them being bridged by slender threads of tissue. The larva thus composed makes its way out of the zooecium, according to Kraepelin through the orifice of a degenerate bud formed for its reception, and swims about for a short time by means of the cilia with which it is covered. Its broad end then affixes itself to some solid object, the polypide is everted through the pore at the narrow end and the whole of that part of the larva which formerly enclosed it is turned completely inside out. A zoarium with its included polypides is finally produced from the young polypide by the rapid development of buds. (b) _From the Statoblast and Resting Buds._ There is little information available as regards the development of the young polyzoon in the resting buds of the freshwater ctenostomes. In _Paludicella_ and _Pottsiella_ the capsule of the bud splits longitudinally into two valves and the polypide emerges between them; but in _Victorella bengalensis_ one of the projections on the margin of the bud appears to be transformed directly into the tip of a new zooecium and the capsule is gradually absorbed.