182 A. Alcock — Car etiological Fauna of India. [No. 1, 



Carapace broad, transversely oblate-oval, moderately convex fore 

 and aft, slightly convex or nearly flat from side to side ; the regions, 

 except the gastric, little defined ; the surface smooth, or granular, often 

 rugose anteriorly. 



Anterolateral borders of good length, strongly arched, usually 

 broadly crenate or lobulate : postero-lateral borders convergent, usually 

 about as long as the antero-lateral. 



Front rather broad (considerably more than a fourth the greatest 

 breadth of the carapace) obliquely deflexed, cut into four lobules or 

 teeth of about equalsize, separated from the orbit by a notch. 



Orbits deep, rather small, the grooves near the outer angle in- 

 conspicuous : eyes on short thick stalks. The antennules fold nearly 

 transversely. 



Basal antennal joint prolonged between the side of the front and 

 the orbital plate ; the flagellum, which is very small (about half the 

 major diameter of the orbit in length), stands in the orbital hiatus. 



The ridges of the endostome, defining the expiratory channels, 

 are very strong, and the opposed margin of the merus of the external 

 maxillipeds is notched, usually very deeply, so that a permanent 

 expiratory orifice results. 



Chelipeds massive, unequal in both sexes; the fingers of good 

 length, pointed not hollowed. In the Indian species there is a very 

 large tooth at the base of the dactylus of the larger hand. 



The abdomen of the male consists of 7 segments. 



Key to the Indian species of Osius. 



I. Carapace more than § as long as broad, scabrous, more 

 or less studded — like the wrists and hands — with salient 



pearly tubercles 0. tuberculosus. 



II. Carapace | as long as broad, smooth to feel, no tubercles ; 

 surface of wrists and hands — all or part — reticulate 

 rugulose O.rugulosus. 



104. Ozius rugulosus, Stimpson. 



Ozius rugulosus, Stimpson, Proc. Ac. Nat. Sci. Philad. 1858. p. 34 : Heller, 

 Novara Crust, p. 22, pi. iii. fig. 1 : A. Milne Edwards, Nouv. Archiv. du Mns. IV. 

 1868, p. 71, and IX. 1873, p. 240, pi. xi. fig. 3 : Miers, P. Z. S. 1877, p. 135: Haswell, 

 Cat. Austral. Crust, p. 63 : Cano, Boll. Soc. Nat. Napol. III. 1889, p. 204 : Ortmann, 

 Zool. Jahrb., Syst., VII. 1893-94, p. 477, and in Setnon's Forschungsr. (Jena. Denk. 

 VIII. ) Crust, p. 53. 



Carapace two-thirds as long as broad, its surface everywhere finely 

 pitted but not rough, a good deal rugulose and finely eroded just inside 

 the antero-lateral borders : gastric region fairly well defined and in- 



