776 



CRUSTACEA. 



b, c, mandible, in different positions; d, lower lip; e, maxilla of first 

 pair ; /, maxilla of second pair. 



Nassau and Good Success Bay, Fuegia, along shores, under stones. 



This species, as collected in Nassau Bay, where it is common and of 

 large size, has the following characters. Three posterior thoracic 

 segments scarcely shorter than three preceding. Caudal lamellae lan- 

 ceolate, equal, both obtuse ; the inner reaching as far back as line of 

 apex of abdomen. Outline of abdomen arcuate either side, and rather 

 narrowly rounded at apex; its surface evenly convex, so that a 

 medial longitudinal line is very nearly straight, or with a slight con- 

 vexity. The epistome is but little broader posteriorly than its length. 

 Flagellum of second antennas eighteen to twenty-jointed. The texture 

 of the shell corneous, as usual. Mandible with black or brownish- 

 black summits ; in a profile view (showing the breadth of the sum- 

 mit, the triturating edge extending inward from the ventral surface 

 in the animal), there are three tooth-like prominences; the apical 

 two are stout, oblong, and corneous, obtusely pointed ; the outer has 

 a notch just below the summit, and the other bears a cluster of setae, 

 the lower of which are gradually longer ; the third prominence has a 

 broad truncate summit, which is minutely scabrous or denticulate. 

 The palpus of the mandible consists of three oblong joints ; the second 

 is longest, and on outer apex there are a few ciliae ; the third joint is 

 curved acute, and has a few short setae on the margin below the apex. 

 Lower lip bilobate, lobes large, rounded, margin edged with extremely 

 short spines or stiff hairs. Upper lip subtriangular, nearly equilateral, 

 anterior angle broad and rounded, posterior side convex, others con- 

 cave. 



Spheroma calcaeea. 



Testa calcarea, Icevis. Thorax posticd paulo latior et depressior. Seg- 

 mentum abdominis posticwn subtriangulatum, superficie convexum, 

 extremitate paulo productum angustum et obtusum. Appendices cau- 

 dales abdomine pared breviores, lamellis subcequis, Janceolatis, obtusis. 

 Pedes mediocres, articulis Ztio ito btoque densh villosis. Flagellum an- 

 tennarum 2-darurn li-lQ-articulatum. 



