Isopoda.
Genus Apseudes, Leach.

(Bate's and Westwood's “British Sessile-eyed Crustacea,” vol. ii., p. 144.)

Apseudes latus, sp. nov. Pl. xvii., fig. 1, a to h.

Body broad, vertically compressed; pereion of same width throughout its whole length; pleon narrowing considerably posteriorily; sides of segments of pereion and pleon fringed with long sparsely plumose hairs. Head produced into a bluntly ended triangle between the antennæ. Upper antenna with the first joint of peduncle rather short, stout, especially at the centre where the width is about half the length, long hairs on outer edge and at inner distal angle; second joint not quite one-third the length of the first, fringed with hairs on both sides; third smaller; secondary flagellum rather more than half the length of the primary, which is slightly longer than the first joint of peduncle. Lower antenna small, about as long as peduncle of upper; of the joints that are visible the first two are short and stout, second bearing a small oval plate with four or five long hairs. First pair of gnathopoda small; carpus more than twice as long as broad; propodos stouter than carpus, produced into a stout fixed finger, which narrows abruptly to a sharp point, has the inner edge minutely crenulated, and is supplied towards the extremity with several setæ; dactylos with a stout tooth on the inner edge near the base, ending very acutely, supplied with short setæ on inner edge, and a few longer ones on the side. Second pair of legs with the carpus nearly quadrangular with two stout spines on posterior margin; propodos not expanded, longer than carpus but more slender, three or four stout spines on posterior margin, one slender one, nearly as long as the dactylos, at the end. Third and fourth pairs of legs similar to the second. Fifth having the ischios and meros both short and supplied with long setæ; carpus about as long as the propodos; a spine at its antero-distal angle; propodos expanded distally, extremity rounded and thickly fringed with