TRANSVAAL CRUSTACEA. 
Part II. 
Notice of a Freshwater Amphipod from South Africa. 
By Paul A. Methuen. 
Family Gammaridea Leach. 
Genus Ft ter ang onyx Stebbing. 
Eucrangonyx robertsi Methuen. 
SUFFICIENT is now known of the fauna of South Africa to show us that 
nearly all the groups of animals found in this country include some 
creatures which are peculiar to it, and are also often lacking in forms 
dominant in other parts of the world. In the class Crustacea we find 
these facts admirably illustrated. We learn, however, that the three 
orders embracing these creatures are wholly unrepresented, and we are 
aware of the fact that freshwater crabs (Thelphusidae) and freshwater 
prawns (Atyidae and Palaemon) are the only Crustacea Malacostraca 
recorded from our rivers, : * whereas the Crustacea Entomostraca are 
represented not only by forms having a wide distribution and which may 
range into the tropics, but by genera which are peculiar to South Africa. 
Huxley, in “ The Crayfish ” (p. 336), makes the following remarks : 
“ In warm climates . . . not only the large prawns, . . . but 
Atyae and fluviatile crabs ( Thelphusa ) compete for the possession of the 
fresh waters ; and it is not improbable that, under such circumstances, 
they may be more than a match for crayfishes ; so that the latter might 
either be driven out of territory they already occupied, as Astacus 
leptodactylus is driving out A. nobilis in the Russian rivers, or might be 
prevented from entering rivers already tenanted by their rivals. 
“ In connection with this speculation, it is worthy of remark that the 
area occupied by the fluviatile crabs is very nearly the same as that zone 
of the earth’s surface from which crayfish are excluded, or in which they 
are scanty. That is to say, they are found in the hotter parts of the 
eastern side of the two Americas, the West Indies, Africa, Madagascar, 
southern Italy, Turkey and Greece, Hindustan, Burmah, China, Japan, 
and the Sandwich Islands. The large- clawed fluviatile prawns are found 
in the same regions of America, on both east and west coasts, in Africa, 
southern Asia, the Moluccas, and the Phillippine Islands ; while the 
Atyidae not only cover the same area, but reach Japan, extend over 
Polynesia to the Sandwich Islands on the north and New Zealand on the 
south, and are found on both shores of the Mediterranean ; a blind form 
( Troglocaris schmidtii ), in the Adelsberg caves, representing the blind 
Cambarus of the caves of Kentucky.” Madagascar, however, must be 
added to the list of countries in which species of Palaemon and Atyidae 
* It is true that one linds amphipods in freshwater or brackish vleis on the Cape Flats 
and in the Cape Peninsula ; but these Crustacea are without doubt animals which have 
become accustomed in very late times to a mode of life neither marine nor yet truly 
freshwater. 
