described as ' semi-pellucid, of a clear golden yellow colour, with a diffuse minium-red pigment on the back, forming slight ramifications on each side of the segments.' The head has an evenly-rounded front, and is roughened with little tubercles, of which there are transverse rows also on the segments of the perason or middle body. The earlier segments of this part have the postero-lateral corners rounded, the sixth and seventh are angularly produced backwards. The second antennas have the flagellum four-jointed. In the last pair of legs there is a dense ciliation on the outer margin of the sixth joint, and in this the finger to some extent participates. The single specimen procured appears to be a female, as it is without the dentiform projection at the base of the fourth joint, described as characteristic in the seventh pair of legs of the male. From the same locality was derived a solitary specimen of Haplophtbalmus mengii (Zaddach), not previously recorded in this country. The generic name intimates that the eyes are simple, a character shared as we have seen with the preceding species, with which it agrees also in the ciliated margins of the seventh pair of feet and various other details. But it has also characters by which it is easily distinguished. It is paler and smaller, being white in colour and barely an eighth of an inch in length. The head has a triangular front, and dorsally from about the middle it is traversed by longitudinal ribs, which are repeated in six lines on the segments of the person. On the third segment of the pleon are a submedian pair of ribs, which are very distinctive, as nothing of the kind is found on H. danicus or allied species in neighbouring genera. The beauty of this little crustacean is attested by the name H. elegans, given to it by Schobl, who wrongly supposed it to be a new species when instituting for it the genus Haplophtbalmus in 1860.
Of the family Oniscidæ there are several species in this district. For convenience of recognition they may be divided into two sets, those that have the flagellum of the second antennas three-jointed, and those in which it is two-jointed. To the former belongs Philoscia muscorum (Scopoli), a lively, shining, often brightly coloured species, considerably larger than the members which have been discussed of the preceding family. It resembles them in regard to the contracted pleon and the well displayed uropods, but its eyes are more strongly developed, its antennae are not spiny, and the apex of its body is acute. Miss Johnson has sent it from Lane End, and Mr. Webb reports it from several places, to which no doubt innumerable additions could be made by simply extending the search. Similarly Oniscus asellus, Linn., is reported from Iver, Langley, Eton, Eton Wick, Hedsor, Burnham Beeches and Fulmer. This large and broad, rather smooth, slow-moving crustacean is tolerably well known. The contour of the peraeon and pleon here present the continuous lateral curves of an oval, in contrast to the interrupted lines of all the preceding species. Moreover, the inner branch of the uropods in this and most of the species to be subsequently mentioned is almost hidden beneath the apical part of the body, the outer branch alone pro- jecting conspicuously. From Hedsor Mr. Webb has submitted to me
114
