FAM. CUNANTHIDAE.—Narcomedusae with large gastral diverticula corresponding in position with the bases of the tentacles. _Cunina_ and _Cunoctantha_, occurring in the Mediterranean and in the Atlantic and Pacific Oceans, belong to this family. In _Cunina_ the tentacles may be eight in number, or some multiple of four between eight and twenty-four. In _Cunoctantha_ the number of tentacles appears to be constantly eight. FAM. PEGANTHIDAE.—There appear to be no gastral pouches in this family. The species of _Pegantha_ are found at depths of about 80 fathoms in the Indian and Pacific Oceans. FAM. AEGINIDAE.—The large gastral pouches of this family alternate with the bases of the tentacles. _Aegina_ occurs in the Atlantic and Pacific Oceans. _Aeginopsis._ FAM. SOLMARIDAE.—In this family the gastral pouches are variable, sometimes corresponding with, sometimes alternating with, the bases of the tentacles. The circular canal is represented {297}in some genera by solid cords of endoderm. _Solmaris_ sometimes appears in the English Channel, but it is probably a wanderer from the warmer regions of the Atlantic Ocean. It is found in abundance during November on the west coast of Ireland. ORDER IX. SIPHONOPHORA. In this order the naturalist finds collected together a number of very beautiful, delicate transparent organisms to which the general term "jelly-fish" may be applied, although their organisation is far more complicated and difficult to describe than that of any of the Medusae. In several of the Hydrozoa the phenomenon of dimorphism has already been noticed. In these cases one set of individuals in a colony performs functions of stinging and catching food and another the functions of devouring and digesting it. In many of the Siphonophora there appears to be a colony of individuals in which the division of labour is carried to a much further extent than it is in the dimorphic Hydrozoa referred to above. Not only are there specialised gastrozooids and dactylozooids, but also gonozooids, zooids for propelling the colony through the water ("nectocalyces"), protective zooids ("hydrophyllia"), and in some cases a specialised zooid for hydrostatic functions; the whole forming a swimming or floating polymorphic colony. But this conception of the construction of the Siphonophora is not the only one that has met with support. By some zoologists the Siphonophoran body is regarded not as a colony of individuals, but as a single individual in which the various organs have become multiplied and dislocated.