CRUSTACEA NORTH PACIFIC EXPLORING EXPEDITION II5 



The color in life is bluish-gray above, clouded with blackish 

 punctse. Sometimes entirely black. Outer and under sides of 

 hands reticulated with purplish. Below white. 



It inhabits the shores of protected harbors, among" stones. A 

 lighter-colored variety lives in sandy coves, along the edges of salt 

 marshes. It also frequents the vicinity of the mouths of small 

 streams. 



Found by us at Loo Choo, at the Bonin Islands, the Hawaiian 

 Islands, and at Tahiti. The species appears to be found at all the 

 tropical Pacific islands, both north and south of the equator. 



183. METOPOGRAPSUS QUADRIDENTATUS Stimpson 



Plate XVI, Fig. 2 



Metopograpsus quadridciitatits Stimpson, Proc. Acad. Nat. Sci. Phila.. x, 

 p. 102 [48], 1858. 



Carapax quadrangular; proportion of length to breadth, i: 1.22. 

 It is considerably narrowed behind, rather smooth, glossy, very 

 moderately striated anteriorly and at the sides ; the posterior half 

 perfectly smooth about the middle. Pregastric lobules little promi- 

 nent. Frontal region smooth, concave or transversely shallow, 

 channel-shaped. Front broad ; margin undulated and sharply cren- 

 ulated. Lateral margin with one very sharp tooth behind the orbital 

 angle. Inner margin of meros-joint of the chelipeds with three 

 or four small tuberculiform teeth near the base and four acute teeth 

 at the anterior angle, the outer tooth very prominent, compressed, 

 with convex outer margin. Carpus with somewhat scabrous or 

 squamous upper surface, and a short, vertical 2- or 3-toothed crest 

 at the inner angle. Hand obsoletely squamous or tuberculous 

 above, below, and within ; outer surface smooth. Ambulatory feet 

 sparsely hairy toward extremities ; terminal spines or teeth of 

 nieros, above and below, strong and sharp. Dimensions of the 

 male: Length of carapax, 0.74; breadth, 0.9; breadth of front, 0.54; 

 length of ambulatory foot of the second pair, 1.4 inches. 



The only other quadridentate Metopograpsus known is .1/. ocean- 

 icits Milne Edwards (Grapsiis occaniciis Hombr. and Jac(|., \'oy. au 

 Pole Sud, Crust., pi. \'i, fig. 9), from which the species above de- 

 scribed differs widel\- in its smoother carapax and hands. 



It was found at Cum-sing-mnon, near Macao, China, ruiniing 

 about between tide marks. 



