Stenothoe valida Dana.

Stenothoe validus Dana, 1853–55, p. 924, pl. 63, fig. 1, a-o. S. valida Stebbing, 1906, p. 194; Walker, 1910, p. 621; Kunkel, 1910, p. 16;. Chevreux, 1913, p. 3. S. valida (part) Della Valle, 1893, p. 566, pl. 58, figs. 74–78; Chilton, 1923, p. 95. S. adhaerens Chilton, 1892, p. 259 (? not Stebbing, 1888, p. 1999). S. assimilis Chevreux, 1908, p. 4; Walker, 1910, p. 621. Montagua miersii and M. longicornis Haswell, 1880, p. 323, pl. 24, figs. 4, 5. Montaguana miersii Chilton, 1883, p. 79. Probolium miersii Chilton, 1885, p. 1043. Stenothoe miersii Stebbing, 1906, p. 200. ? Stenothoe dollfusi Chevreux, 1887, p. 327; 1891, p. 260 Stebbing, 1906, p. 196.

This species is common on the New Zealand coasts; and I have series of specimens from several localities. There are great differences in the length of the antennae, especially of the second antenna, and in the shape of the gnathopods, due to age and sex. In the more mature males the second antenna increases very considerably in length, especially in that of the peduncle, and the second gnathopod becomes very large and assumes the form shown in Chevreux's figure of S. assimilis. In addition to this form and the variations in it which are presumably due to age, there is another in which the teeth at the distal end of the palm of the second gnathopod project more or less at right angles to the palm, instead of being a continuation of it as in the first form. This second form appears to be identical with the one described by Chevreux under the name of Stenothoe dollfusi, and it is apparently this form that Kunkel had before him when recording Stenothoe valida from the Bermudas. As I have found the two forms Stenothoe valida and S. dollfusi together on two separate occasions in Cook Strait, and as both forms also occur together in Port Jackson, New South Wales, and apparently elsewhere, I have little doubt that they both belong to one species, and that we have here another example of a species with dimorphic males.

In the older males the mouth-parts appear to become degenerate. I have, however, discussed this question more fully, and also the reasons for referring the species to the one originally described by Dana, in the Records of the Australian Museum, vol. 14, p. 95.

I have recently received specimens from the Hawaiian Islands which appear to belong to this species.

Localities.—Lyttelton; Dunedin Harbour; Cook Strait.

Distribution.—Australia; North and South Atlantic Oceans; Hawaiian Islands.