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Show 1 9 0 4 .] ASELLOTA-GROUP OF CRUSTACEANS. 3 2 1 rounded tubercle below its middle and a couple of minute tubercles or denticles above the large tubercle; the edge is besides furnished with some robust setae, increasing much in length downwards and pectinate along their upper margin ; lower end of palmar edge armed with a strong long spine, the structure of which is shown in fig. 2 e ; seventh joint with its short claw claw-shaped, reaching slightly beyond the palmar edge, along its lower margin with fine setae and a row of small strong spines adorned with a few sawteeth on their lower margin.-In the female the hand is a little smaller and a little shorter in proportion to the depth than in the male, but it differs especially in the palmar edge, which is feebly convex and quite without tubercles; seventh joint and claw as in the male. Abdominal shield a little broader than long. Each lateral margin with four or five minute spines placed at rather long intervals, and terminating in the usual triangular tooth at the conspicuous notch; behind this notch a minute indentation is observed. Posterior margin has its middle portion produced so that a rather low rounded lobe is formed, and almost each half of the margin is moderately concave. Uropoda considerably more than half as long as the abdominal shield; exopod slightly longer than sympod, but considerably shorter than endopod. Distal joint of the endopod of second male pleopoda unusually slender and not widened at or beyond the middle; a short terminal portion only half as broad as the remainder, with the end cut off transversely and without any brush. Length of the largest male 5-5 mm., of an ovigerous female 6 mm. Occurrence. Some specimens were taken by the author at Siracusa, Sicily, in depths from 12 to 25 fathoms; four specimens were secured by the Danish botanist, Dr. Borgesen, at Ajaccio, Corsica. Remarks. This fine species is easily distinguished by the very long process on the basal joint of antennae, by first thoracic legs in both sexes, and by the shape and armature of abdomen.-None of the forms mentioned in Carus's ‘ Prodromus Faunae Mediterranean can be referred to Stenetrium, and the present species seems to be new, though it is probably widely distributed in the western half of the Mediterranean. 4. S ten etr ium h a sw e l l i i Bedd. 1886. Stenetrium haswelli Beddard, Proc. Zool. Soc. London, 1886, p. 103. 1886. Stenetrium haswelli Beddard, Isopoda ii. in ‘ Challenger' Rep. vol. xvii. p. 9, pi. iv. figs. 1-8. The only specimen hitherto known is a male described and figured by Beddard. From his long description most of the characters given below have been selected; some of my statements have been derived from his figures, and from two sketches. P roc. Z ool. S oc.-1904, V o l . II. No. XXI. 21 |