Pilumnus.

The crabs of the genus Pilumnus are not common in the littoral zone in New Zealand; they are somewhat solitary in habit, and rendered inconspicuous by their covering of grey hairs and the flocculent matter entangled in the latter. As moreover they are of sluggish and retiring habits, it is not surprising that they are very imperfectly known. The genus as a whole contains a great number of species, differing for the most part in confusingly small details. We have not revised the New Zealand species in this paper, which therefore has the merit of not adding any new species, though one or two are known to us.

Five species have been reported from New Zealand, but only three of the records appear to be valid. P. vespertilio is a well-known species, common throughout the Indo-Pacific; it was included in Miers' Catalogue, but placed on Hutton's “black list.” Specimens of a species of Pilumnus occasionally found in the tangled holdfast of the seaweed Macrocystis and in similar places in Lyttelton Harbour were sent to Dr. Calman of the British Museum, who replied that they were identical with specimens from New Zealand in the British Museum labelled P. vespertilio by Miers, but that these were certainly not P. vespertilio on the evidence of the other specimens so labelled in the British Museum collection and on the evidence of the description given by Alcock, (Jour. Asiatic Soc. Bengal, 67 (2), 1898, p. 192.). The Lyttelton specimens were referred by Calman to de Man, who reported that they appeared to him to belong to Pilumnus novaezealandiae Filhol. It is quite as certain that the record of P. tomentosus by Miers was also incorrect. Hutton has not named it among the excludenda, but has crossed it off from his copy of the Catalogue; and though it is known in great detail from White-legge's very full description (Mem. Austr. Mus., 4, vol. 2, p. 149, 1900) it has not been recognised in New Zealand. Filhol did not collect either species, but described two more, P. spinosus and P. novae-zealandiae. Although Miss Rathbun considers that Filhol has misunderstood P. tomentosus (Biol. Results “Endeavour” Exped., 1909-14, p. 119), his two new species are apparently both valid. A further species, P. maori, has been described by Borradaile (Brit. Antarct. Exped. 1910, Zoology, vol. 3, p. 99, Fig. 10) from a single very small male, 6 mm. in length, dredged in 70 fathoms near East Cape during the British Antarctic Expedition of 1910, and his description agrees well with some twelve specimens, representing both sexes, in our collections; they are, however, much larger, up to 21 mm. in length, and were collected at Ponui Island, Ponsonby Reef, and Akaroa.