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Show 1904.] ASELLOTA-GROUP OF CRUSTACEANS. 3 2 9 is placed behind the main portion of the edge (as in the females of S. occidental and S. antillense). The " claw " reaches just to the end of the edge ; its lower margin with a number of fine, scarcely serrate spines. Abdominal shield slightly longer than broad. The lateral margin unarmed, only with the usual tooth at the notch ; posterior margin strongly and evenly convex. tJropoda wanting in my specimens. Second joint of the endopod of second male pleopoda increases gradually somewhat in breadth from the base for two-thirds of its length; the distal oval portion is marked off by small lateral indentations, and the outer portion of its lower surface is adorned with a brush of very short fine hairs; the margin turning outwards has a small spine directed forwards a little in front of the indentation named. Length of an adult male 4 mm., of the largest immature female 3-4 mm. Occurrence. Gulf of Siam: between Koh Mesan and Koh Chuen, 38 fathoms (one male) and 15 fathoms (two immature females). The specimens were found in sifted bottom material taken by Dr. Th. Mortensen in the beginning of February 1900. Remarks. This small slender species is easily distinguished from all preceding forms by the small rounded eyes and the complete absence of any process from the lateral margin of the head. First thoracic legs in the male deviate much from those in all other forms hitherto known. 10. Stenetr ium in erm e Hasw. 1881. Stenetrium inerme Haswell, Trans. Linn. Soc. New South Wales, vol. v. p. 480, pi. xix. fig. 2 [teste Haswell]. 1882. Stenetrium inerme Haswell, Catal. Austr. Stalk- and Sessile-eyed Crust, p. 309. This species is mentioned only for the sake of completeness, because I think that it does not belong to Stenetrium. In his ‘ Catalogue' Haswell describes some characters which raise doubt as to the correctness of his own reference to this genus, the type of which is S. armatum Hasw.; tracings of figures* in his first paper corroborate this doubt. According to his fig. 2, the first thoracic segment is laterally not produced into an acute process directed forwards as in all other species; in the text (Catal. p. 309) he says: " Lateral borders of anterior thoracic segments not much produced, bilobed," which thus agrees with the figure. Furthermore, the figure of the maxilliped, the description of the antennulse, having their basal joint " very short and broad," and abdomen, having the lateral margin " entire," thus without notch, all these particulars do not agree with features met with in all other species of Stenetrium ; unfortunately Haswell omits the pleopoda. On hand and " claw " of first thoracic legs * Kindly forwarded to me a long time ago by Mr. R. I. Pocock, now Superintendent of the Zoological Gardens, London. |