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Show 308 MR. G. S. BRADY ON BRITISH MARINK MITES. [Apr. 6, there is a styliform appendage (fig. 6, b). The first three pairs legs are of nearly equal length, the last pair distinctly longer, all gradually tapering from the base and having subequal joints, except the third and penultimate joints, which are short, and the last, which is long, slender, and tapering, and terminates in two delicate claws. The limbs, as well as the body, are beset with stout hairs, the last joints of the legs being rather thickly tufted. Eyes two, lateral, at the base of the second pair of feet. There is a good deal of diversity in the proportions and development of the mandibles and palps in different individuals of this species, probably dependent upon age (or sex?). The more highly magnified figure (fig. 6) seems to me to belong probably to the adult, while the state of the parts shown in the drawing of the entire animal (fig. 5) may be supposed to be characteristic of youth. In some specimens the lower joints of the legs are liable to run out into irregular subspinous processes. G. marinus occurs pretty commonly in crevices of magnesian limestone rocks, between tide-marks, near Sunderland ; and I have a specimen which was washed from amongst the roots of Algae dredged off Cumbrae in the Frith of Clyde. Genus CHEYLETUS, Latreille. CHEYLETUS ROBERTSONI, nov. sp. (Plate XLI. figs. 1-4.) Length -^ oi an inch ; pellucid, smooth, almost colourless. Body broadly ovate, constricted in front of the origin of the first pair of legs, the head and rostrum forming a triangular prominence, the lateral angles of which are much produced ; from the front of these angles spring two very tumid, imperfectly jointed palps, which reach beyond the tip of the rostrum, and terminate in a large curved claw and several long setse, two of which are beautifully pectinated on their inner margins with long, tooth-like cilia: the swollen base of the palp bears a single long hair, which reaches much beyond the point of the terminal claw. The rostrum consists apparently of two opposing triangular plates, from the tips of which spring two small setse. The two hindmost pairs of legs are of nearly equal length, the second somewhat shorter, all bearing a few long scattered hairs, and having long and slender terminal joints which are armed with delicate, doubly curved claws (figs. 3 and 4). The legs of the first pair are much longer and more slender, anten-niform, the joints gradually tapering and increasing in length from first to last: the thighs are moderately remote. Two long lateral hairs spring from near the middle of the body between the second and third pairs of legs ; and there are two lateral tufts of three hairs each near the posterior extremity. One specimen only of this remarkable mite was dredged off Hawthorn, on the Durham coast, in a depth of 27 fathoms. I have named it after m y valued friend Mr. David Robertson of Glasgow, who was my companion on the dredging-expedition when it was taken. The mouth-organs are so like to those of Chei/fefus erudi- |