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Show 546 REV. T. R. R. STEBBING ON CRUSTACEANS [May 22, In regard to that species he says that the second pair of maxillae " have the terminal joint not very large, of a rather regular ovoid form, and but sparingly supplied with bristles." The shape appears from the figure to be rather similar to that in the present species, but the size and armature very different. First maxillipeds to the third peraeopods.-In all these appendages the penultimate joint is longer than the ultimate and, to a less extent, than the antepenultimate, but these three joints combined differ greatly in their relation to the preceding joints, being at least as long as both third and fourth joints in the first maxillipeds, but shorter than the fourth by itself in the third peixeopods. In the second and third peraeopods their length is absolutely as well as relatively shorter than iu the preceding limbs ; but also the length of the third and fourth joints successively increases from the first maxillipeds onwards, and whereas in the first maxillipeds and to a less extent in the second the fourth joint is shorter than the third, in the following appendages it is increasingly longer. The exopods of all these six pairs of appendages have a close general resemblance. Sars, in describing the genus, speaks of the articulation between the peduncle and the flagellum as very oblique, and figures the flagellum as un-jointed. But, at least in the present species, it appears that the flagellum has transverse lines of a feeble aud perhaps evanescent articulation, and that the junction with the peduncle is also transverse, a strongly marked oblique line on the peduncle following the course of a muscle but not constituting an articulation. Claus's figures of E. mulleri seem to be in agreement with this view of the matter. The uropods.-The rami are equal in length, and scarcely reach beyond the insertion of the subapical processes of the telson. The telson.-The subapical processes are quite smooth. The apical piece of the telson between them narrows above the middle, carrying at this point two minute spinules, and then widens, passing with convex margins to an acute apex. Below the middle of its entire length the telson has a pair of dorsal spinules. Length. The specimen of which the parts are figured measured 16 m m . Another measured 18 mm., and a third 21 m m . None had sexually metamorphosed pleopods. Locality. Stanley Harbour, Falkland Islands. Gen. THYSANOESSA Brandt. 1851. Thysanoessa (subgen.), Brandt, Middendorff's Sibirische Beise, Krebse, p. 52. 1882. Thysanoessa, Sars, Christiania Vidensk. Forh. no. 18, p. 52. 1883. Thysanoessa, Sars, Christiania Vidensk. Forh. no. 7, p. 25. 1885. Thysanoessa, Sars, ' Challenger' Schizopoda, Beports, vol. xiii. pp. 63, 119. 1887. Thysanoessa, Hansen, Vid. Medd., Malac. mar. Groenl. occid. p. 54. |
