The development of the Narcomedusae is in the main similar to that of the Trachomedusae, but shows some remarkable features. In _Aeginopsis_ a planula is formed by multipolar immigration. The two ends of the planula become greatly lengthened and give rise to the two primary tentacles of the actinula, of which the mouth arises from one side of the planula. Hence the principal axis of the future medusa corresponds, not to the longitudinal axis of the planula, but to a transverse axis. This is in some degree parallel to the cases described above, in which a planula gives rise to the hydrorhiza, and buds a polyp laterally. In _Cunina_ and allied genera the actinula, formed in the manner described, has a hypostome of great length, quite disproportionate to the size of the body, and is further endowed with the power of producing buds from a stolon arising from the aboral side of the body. In these species the actinula is parasitic upon another medusa; for instance, _Cunoctantha octonaria_ upon _Turritopsis_, _C. proboscidea_ upon _Liriope_ or _Geryonia_. The parasite effects a lodgment in the host either by invading it as a free-swimming planula, or, apparently, in other cases, as a spore-embryo which is captured and swallowed as food by the host. The parasitic actinula is found attached to the proboscis of the medusa; it thrusts its greatly elongated hypostome into the mouth of the medusa and nourishes itself upon the food in the digestive cavity of its host. At the same time it produces buds from an aboral stolon. The buds become medusae by the direct method of budding described above. In some cases the buds do not become detached at once, but the stolon continues to grow and to produce more buds, forming a "bud-spike" (_Knospenähre_), which consists of the axial stolon bearing medusa-buds in all stages of development. In such cases the original parent-actinula does not itself become a medusa, but remains arrested in development and ultimately dies off, so that a true alternation of generations is brought about. It is in these parasitic forms that we meet with the method of reproduction by sporogony described above. In other Narcomedusae, e.g. _Cunoctantha fowleri_ Browne, buds are formed from the sub-umbrella on the under side of the stomach pouches, where later the gonads are developed. _Classification._--Three families of Narcomedusae are recognized (see O. Maas [40]): [Illustration: After O. Maas, _Craspedoten Medusen der Siboga Expedition_, by permission of E. S. Brill & Co. FIG. 67.--_Solmundella bitentaculata_ (Quoy and Gaimard).] 1. _Cunanthidae._--With broad gastric pouches which are simple, i.e. undivided, and "pernemal," i.e. correspond in position with the tentacles. _Cunina_ (fig. 66) with more than eight tentacles; _Cunoctantha_ with eight tentacles, four perradial, four interradial.