ORDER DECAPODA. 147 



This family might, as in many methods anterior to the 

 distribution of these animals by Daldorf, form but a single 

 genus, that of 



Crab, (Cancer.) 



The greatest number have the feet all attached to the sides 

 of the breast, and always exposed. The first five sections 

 are in this predicament. The first, or the Swimmers (Pin- 

 NlPEDES) unites to this character, that of having the final 

 feet at least terminated by a very flatted articulation like a 

 fin, (oval or orbicular, and broader than the same articulation 

 of the preceding feet, even when they also are fin-like.) They 

 remove more frequently from the shore, and proceed into the 

 high sea. If we except the orithyise, the tail of the males 

 presents but five distinctly marked segments, while that of 

 the females has seven. We shall commence with those, all 

 of whose feet, the claws excepted, are natatory. 



Matuta, Fah., 



Have the testa almost orbicular, and armed on each side with 

 a very strong tooth in the form of a spine. The hands are 

 denticulated above, in the manner of a ridge, and bristling at 

 their external face, with pointed tubercles ; and the third 

 articulation of the external jaw-feet is without any apparent 

 notch, and terminates in a point, so that it forms, with the 

 preceding articulation, an elongated and almost rectangular 

 triangle. The external antennae are very small. The ocular 

 pedicles are a little arched. Cancer latipes, Degeer. 



PoLYBiUS, Leach. 



Approximate to the Portmii ; but their testa is proportionably 

 less broad, and more rounded. I ts sides only present the 



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