On a neic Si^ecies of Sessile-eyed Crustacean. 73 X. — Description of a new Species of Sessile-eyed Crusta-cean, and other Notices. By the Rev. Thomas R. R. Stebbing, M.A. [Plates IV. & v.] Microdeuteropus bidentatus, n. sp. PI. IV. figs. 1,1 a, lb. This new species of Microdeuteropus was dredged at Sal-combe in August of the present year (1875). It exhibits well the characters of the genus as given by Messrs. Bate and Westwood, if we except the expi*ession '"'' complexly sub-ehelate," which they apply to the first gnathopods. This complexity, however, does not belong to all the species they describe, nor to the females of any of them. The genus Autonoe of Bruzelius Avas separated from Microdeuteropus of Costa to receive species which do not possess the complexity in either sex, and which have the rami of the last pair of pleopoda unequal. But the separation seems scarcely desirable, since there appears to be no correlation between the two cha-racters used for the generic distinction. Thus the present species and M. longipes, at least as described in the 'Cata-logue of Amphipodous Crustacea,' have the rami of the last pleopoda equal, but the hands not complexly chelate. On the other hand, M. grandimanus, also described in the Cata-logue just mentioned, has the rami of the pleopoda unequal, but the posterior angle of the carjras of the first gnathopods produced into a tooth in the male — a circumstance which links it closely to the M. gryUotalpa of Bate and Westwood, M. anomalus of Rathke. In general appearance the new species has a near re-semblance to M. Websteri. The superior antennae have a secondary appendage of three slender articulations, and a flagellum of fifteen. In the lower antennse the articulations of the flagellum are comparatively stout, but only four in number. The eyes are small and black. The whole animal is slender, and, like others of the genus, when dead has a metallic lustre. The telson has a double apex, carrying two short spines and two setae. The last pair of legs exceeds in length the preceding pair by the whole of the long thin pro-podos and finger ; the antepenultimate pair is the shortest ; the third and fourth pairs are equal in size, having the finger two thirds the length of the propodos. The thighs of all the seven pairs of legs are long ; those of the second gnathopods are distinguished by a sort of curved spur projecting at the anterior distal angle ; in other respects this pair of gnathopods
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