Jassa frequens (Chilton). (Fig. 4, A to D.)

Podocerus frequens Chilton, 1883, p. 85, pl. 3, fig. 2. P. latipes Chilton, 1884, p. 258, pl. 19, fig. 2 a-d. Jassa frequens Stebbing, 1906, p. 656.

This species was described under the name Podocerus frequens in 1883 from a number of small specimens obtained in Lyttelton Harbour, and although male and female were described it is probable that none of them were quite fully developed. In the following year other specimens similar in general character but differing somewhat in the second gnathopods, and particularly in the greatly broadened character of the fourth peraeopod, were obtained from the same locality and were named Podocerus latipes, it being suggested, however, that they might prove to be only a variety of P. frequens. In 1906 Stebbing combined these two species under the name Jassa frequens, regarding the form described as P. latipes as the male.

The species is fairly common in Lyttelton Harbour at the roots of Macrocystis and other seaweeds above low-water level, and I have numerous specimens and can therefore add something to the descriptions previously given. I am not certain about the generic position of this species, but on the whole it seems to come within the characters of Jassa, the name now adopted for the genus Podocerus, except that I cannot find upturned teeth on the outer ramus of the third uropod, both rami being apparently free from these teeth. The broadened character of the fourth peraeopod proves, however, not to be confined to the male, but to be present also, sometimes apparently even to a greater degree, in the female. The differences between the two sexes in the second gnathopod are not greatly marked, but in the female the palm of the propod is slightly concave and the basal part of the propod is not produced into a distinct process as it is in the male; in the male this process is stout and truncate at the end, but the whole gnathopod is not greatly larger than in the female. One or two specimens, however, which, from the shape of the second gnathopod, would be considered males, bear brood-plates on some of the peraeopoda.