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Show 1885.] MR. MIERS ON A THELPHUSA FROM KILIMA-NJARO. 237 6. Description of a new Variety of River-Crab, of the genus Thelphusa, from Kilima-njaro. By E. J. MIERS, F.L.S., F.Z.S. [Received February 3, 1885.] The species of Thelphusa, or River-Crabs, are extremely numerous, and their discrimination is often very difficult, on account of the changes which the species undergo as they increase in age and size. In the collection brought by Mr. H. H . Johnston from Kilimanjaro are two specimens of this genus, which I assign, though not without some hesitation, to the Thelphusa depressa, Krauss, described from types taken near Pietermaritzburg, Natal. They agree with the description and figure in their depressed carapace, which is considerably dilated at the branchial regions, in the non-development of the lateral epibranchial tooth, and in other essential characters; but differ in the more strongly defined cervical suture of the carapace, and the more strongly denticulated merus, and much less strongly arcuated dactylus of the chelipedes. As regards this latter character, I may observe that in a series of Thelphusce (perhaps T. difformis) in the Museum collection, the dactyli of the chelipes are in some males arcuated, and in others nearly straight. I append a detailed description of the specimens from Kilimanjaro, which I propose to designate T. depressa, Krauss, var. johnstoni, but which may prove to belong to a distinct species. THELPHUSA DEPRESSA, Krauss, var. JOHNSTONI. Cf. Thelphusa depressa, Krauss, Sudafrik. Crustaceen,p. 38, pi. 11. fig. 4 (1843). Carapace transverse, widest in its post-frontal region, depressed, with the dorsal surface nearly smooth, and divided into two nearly equal portions by the zigzag cervical suture, which extends transversely across the carapace to the postero-lateral margins; behind this a second transverse depression (not a suture) crosses the carapace behind the cardiac region. The postfrontal crest extends to the antero-lateral margins of the carapace, and is interrupted only by the meso-gastric suture, which bifurcates posteriorly (as usual in the genus) ; this crest is granulated near to the antero-lateral margins, which are defined by a distinctly granulated line; the lateral epibranchial teeth are not developed. On the hepatic and branchial regions are several faintly indicated lines, which extend inward for a short distance over the dorsal surface of the carapace from the lateral margins. The front is about one third the width of the carapace, punctulated above, with its anterior margin sinuated, its antero-lateral angles obtuse and not prominent. The orbital margins are entire, and defined by a raised line, which is granulated except near to the front; the inferior orbital margin is regularly arcuate, not (as in T. perlata) angulated near to the interior sub-ocular lobe, which is not at all prominent; the tooth, also, at the exterior orbital angle is very little developed ; the parts of the |