16 S. I. Smith on Brazilian Crustacea. 



Cardiosoma quadratum Saussure 



Girdisomi quairobtrt, Saussare, op. cit, p. 22, pi. 2, fig. 13, 1858. 

 GirMsomi, diurwn G-lll, Aauils Lye. Nat. Hht., New York, vol. vii, p. 42, January, 

 1859. [Wrongly printed 1858 on the third signature.] 



A number of specimens were collected at Pernambuco. 



It is at ouce distinguished from the G. Guanhumi by the more 

 quadrate form of the carapax, the branchial i-egions being much less 

 swollen, by the latei'al margin being marked by a distinct carina in- 

 stead of evenly rounded, and by the sharply triangular and spiny 

 merus of the chelipeds. Some of the specimens collected by Prof. 

 Hartt are nearly as large as ordinary specimens of G. Guanhumi and 

 still retain the distinctive! characters, so that it seems scarcely possible 

 that it can be the young of that species as suggested by Saussure. 



This species is in fact more nearly allied to the G. carnifex tlian to 

 G. Guanhumi, and it resembles so closely a species in the collection 

 of the Peahody Academy of Science from the west coast of Afi-ica 

 — apparently the C. armatum of Herklots, — that it might readily be 

 mistaken for it. The African species diifers however in having the 

 carapax less convex and the carina of the lateral margin less promi- 

 nent ; tlie front is broad and high, the anterior lobes of the gastric re- 

 gion are protuberant and the depressed space between them and the 

 frontal margin is coarsely granulous, while in the quadratum the an- 

 terior gastric lobes are not protuberant and the depressed space be- 

 tween them and the frontal margin is scai'cely granulous. The epis- 

 tome and the nasal lobe are quite different in the two species ; in the 

 quadratum the spistome is nearly straight and its anterior margin is 

 not granulated, the nasal lobe is high, forming rather more than a 

 semicircle, and the lobes of the front on each side of it do not reach 

 down to the anterior margin of the epistome, while in the African 

 species the epistome is higher, inore curved and the anterior margin 

 granulated in the middle, and the nasal lobe is much lower, so that 

 the lobes of the front on each side of it reach quite down to the an- 

 terior mai'gin of the epistome. Finally the chelipeds and ambulatory 

 legs in the African species are more spiny and granulous. 



Specimens of G. quadratum give the following measurements: — 



Male. Male. Female. Female. 



Length of carapax, 42-6mm 45 6mm 43-3mm 46-8mm 



Breadth of " 



Ratio of length to breadth, 



Length of merus in right cheliped, 



"" " hand " " 



" " merus in left " 

 " hand " " 



