Paracorophium excavatum (G. M. Thomson).

Corophium excavatum, G. M. Thomson in Trans. N.Z. Inst., vol. xvi, p. 236, pl. xii, figs. 1-8 (1884). Paracorophium excavatum, Hutton in Index Faunae N.Z., p. 261 (1904). Paracorophium excavatum, Chilton in P.Z.S. London, 1906, p. 704 (1906). Paracorophium excavatum, Stebbing in “Das Tierreich Amphipoda,” p. 664 (1906).

This species was originally described by Mr. Thomson from the Brighton Creek (salt water), near Dunedin. Subsequently I took it from the same creek at a time when the water was almost fresh, and specimens lived in some of the some water for several months. I have also specimens taken from brackish water at Napier. Messrs. Lucas and Hodgkin afterwards took it near Lake Rotoiti (5 fathoms), and in Lake Waikare, where, of course, the water is perfectly fresh. It therefore appears to be one of several species of our New Zealand Amphipoda that are able to live either in salt or in fresh water.

So far as I am aware, it is the only known fresh-water species of the family Corophiidæ.