As in the northern temperate zone, so in the southern, the number of individuals and the variety of forms is much less than between the tropics. This is especially apparent on comparing the numbers of species constituting a genus. In this zone genera composed of more than ten species are the exception, the majority having only from one to five. The proportion of genera limited to this zone is rather high; they will be indicated under the several districts, which we distinguish on geographical rather than zoological grounds. 1. The _Cape of Good Hope_ district. The principal genera found in this district are the following (those limited to the entire zone being marked with a single (*) and those peculiar to this district with a double (**) asterisk):-- _Chimæra_, *_Callorhynchus_, _Galeus_, **_Leptocarcharias_, _Scyllium_, _Acanthias_, _Rhinobatus_, _Torpedo_, _Narcine_, _Astrape_, _Raja_. _Serranus_, _Dentex_, _Pristipoma_; _Cantharus_, _Box_, **_Dipterodon_, _Sagrus_, _Pagrus_, _Pagellus_, _Chrysophrys_; *_Chilodactylus_; _Sebastes_, *_Agriopus_; _Trigla_; _Sphyræna_; _Lepidopus_, _Thyrsites_; _Zeus_; _Caranx_; _Lophius_; _Clinus_ (10 species), _Cristiceps_; **_Chorisochismus_. *_Halidesmus_, *_Genypterus_, _Motella_. _Syngnathus_.--*_Bdellostoma_. This list contains many northern forms, which in conjunction with the peculiarly southern types (_Callorhynchus_, _Chilodactylus_, _Agriopus_, _Clinus_, _Genypterus_, _Bdellostoma_) leave no doubt that this district belongs to the southern temperate zone, whilst the Freshwater fishes of South Africa are members of the tropical fauna. Only a few (_Rhinobatus_, _Narcine_, _Astrape_, and _Sphyræna_) have entered from the neighbouring tropical coasts. The development of Sparoids is greater than in any of the other districts of this zone, and may be regarded as one of its distinguishing features. 2. The _South Australian_ district comprises the southern coasts of Australia (northwards, about to the latitude of Sydney), Tasmania, and New Zealand. It is the richest in the southern temperate zone, partly in consequence of a considerable influx of tropical forms on the eastern coast of Australia, where they penetrate farther southwards than should have been expected from merely geographical considerations; partly in consequence of the thorough manner in which the ichthyology of New South Wales and New Zealand has been explored. On the other hand, the western half of the south coast of Australia is still almost a _terra incognita_.