ACADEMY OF SCIENCES. 147 



No. 51. Male and female. Magdalena Bay, in spirits. Fisher and Lock- 

 ington. 



G. heteropthalmus. S. T. Smith, loc. tit., 116, pi. 11, f. 6; pi. Ill, f. 1-16. 

 Gulf of Fonseca, West Coast Central America. 



G. Keteropleurus. S. I. Smith, loc. tit, p. 118, pi. 11, f. 7; pi. Ill, f. 2-26. 

 Gulf of Fonseca, W. C. Cent. Amer. 



G. armatus. S. T. Smith, loc. tit., p. 123, pi. 11, f. 5; pi. Ill, f. i-id. Gulf 

 of Fonseca. 



G. ortwtus. S. T. Smith, loc. tit, 125, pi. 11, f. 9-9a; pi. Ill, f. 5-5c. W. C. 

 Cent. Amer. 



G. brevifrons. Stimpson. Ann. Lye. Nat. Hist., New York, vol. vii., p. 229. 

 S. T. Smith, loc. tit, 131. 



I have not seen Stimpson's description of this species, but from Smith's 

 comparison of its carapax with that of G. minax, I conclude that several 

 specimens collected by Mr. Fisher on the West Coast of Lower California, 

 belong to this species. The meros of tbe larger cheliped is stout, triquetral, 

 and marked on its exterior surface with transverse setose striae; the carpus 

 has a rounded tooth at its inferior distal end, and the manus is large and 

 heavy, twice as large as the width of the carapax, the palmar portion rounded 

 and smooth, but minutely granular on the outside, and on the inside beset 

 with small tubercles on its more elevated portions. The depression for the 

 carpus is short but very deep, the thin upper edge of manus curving inwards 

 over it. The propodal finger is slightly deflected downwards, and the dac- 

 tylus curved from the base, the curve increasing towards the tip. The 

 tubercles of the inner edges ot the fingers are very indistinct, except one 

 near the centre of the propodal finger, and another close /to the tip, which 

 thus appears bifid. 



In the smaller cheliped the tips of the fingers are obtuse and rounded, and 

 the outer edges raised, so that they are imperfectly spoon-shaped. The dac- 

 tylus and propodal finger are almost parallel and near each other, but touch 

 only at the tip, where they have a few setae . 



The meral segments of the ambulatory legs are plicate, like those of the 

 chelipeds. 



Following are the dimensions of two large specimens: 



M. M. M. M. 



Length of carapax 17 13 



Width of carapax • • . 23 19 



Length of larger hand 45 



The fourth, fifth, and sixth segments of the abdomen in the male are not 

 united. 



