Major Walton also notes that in the United Provinces the growth of _Hislopia_ is at its maximum during "rains," and that at that time of year almost every adult _Paludina_ in a certain tank at Bulandshahr had its shell covered with the zooecia. The Calcutta race flourishes all the year round but never forms large or closely compacted zoaria, those on shells of _Vivipara_ exactly resembling those on leaves of _Vallisneria_. In Calcutta both eggs and spermatozoa are produced at all times of the year simultaneously in the same zooecia, but the eggs in one zooecium often vary greatly in size. When mature they reach relatively considerable dimensions and contain a large amount of food material; but they are set free from the zooecium as eggs. They lie loose in the zooecium at a comparatively small size and grow in this position. Nothing is known as regards the development of _Hislopia_. Both forms of the species appear to be confined to water that is free from all traces of contamination with brine. Order PHYLACTOLÆMATA. The polypide in this order possesses a leaf-like ciliated organ (the epistome) which arises within the lophophore between the mouth and the anus and projects upwards and forwards over the mouth, which it can be used to close. The zooecia are never distinct from one another, but in dendritic forms such as _Plumatella_ the zoarium is divided at irregular intervals by chitinous partitions. The lophophore in most genera is horseshoe-shaped instead of circular, the part opposite the anus being deeply indented. There are no parietal muscles. The orifice of the zooecium is always circular, and there is no trace of any structure corresponding to the collar of the ctenostomes. The tentacles are always webbed at the base. All the phylactolæmata produce the peculiar reproductive bodies known as statoblasts. The phylactolæmata, which are probably descended from ctenostomatous ancestors, are confined to fresh or slightly brackish water. Most of the genera have a wide geographical distribution, but (with the exception of a few statoblasts of almost recent date) only one fossil form (_Plumatellites_, Fric. from the chalk of Bohemia) has been referred to the order, and that with some doubt. It is convenient to recognize two main divisions of the phylactolæmata, but these divisions hardly merit the distinction of being regarded as suborders. They may be called Cristatellina and Plumatellina and distinguished as follows:-- Division I, PLUMATELLINA, nov.--Ectocyst well developed; zoaria without a special organ of progression; polypides contained in tubes. Division II, CRISTATELLINA, nov.--Ectocyst absent except at the base of the zoarium which is modified to form a creeping "sole"; polypides embedded in a common synoecium of reticulate structure.