BRACHYURI. 161 



It seldom, if ever, attains any considerable dimensions, as the body, 

 shell, or carapace of thow apparently full grown in this country, may 

 ! inscrilHxl in a broad oval outline of about three inches by two. 

 Hundreds are found of all inferior sizes. The shell is slightly convex, 

 the sides and anterior edge curving, but interrupted by notches, the 

 posterior margin almost in a straight line. 



In front arc two eyes, on peduncles of the shell, and four tentacular 

 organs near the edge, two of them like stout bristles, exterior, and two 

 shorter, nearer the region of the mouth, which is below, forked, and in 

 constant motion. The eyes on peduncles rise from a socket in the edge 

 of the shell, outside the longer antenna), each folding down for insertion 

 to right and left in its respective socket. They are most prominent 

 during life. 



Two broad, thin, maxillary organs below, exercise a horizontal 

 action, like scissors, or the blades of two knives, as the animal feeds. 



The Cancer mernas is provided with ten limbs, being two claws and 

 eight legs. In all the tribe the claws are differently formed, being 

 larger and stronger than the legs. They have several important part? 

 to perform ; first, in holding the food, tearing it asunder, and carrying 

 it to the mouth. They are likewise the organs of defence, and the in- 

 struments of offence. The limbs, disposed in pairs, are adapted for run- 

 ning, and resemble each other, only those of the hind pair ore fringed, 

 and slightly flattened. Many other Crustaceans have a greater number 

 of limbs, besides some apparently imperfect or abortive, and a kind of 

 auxiliary finny organ to aid their movements. 



The claws, however, are the main and most important organs, 

 armed with forceps, whose office may be compared to the hands of 

 mankind, and the paws of other animals. They possess remarkable 

 strength, in proportion to their dimensions. 



The Crustacean class is often compared to Insects, with which it was 

 formerly conjoined ; and many analogies, at least in form, will be allowed 

 to subsist between them. But characters equally distinctive, are de- 

 ficient. For example, I have seen no indication, in any species, of the 

 same intelligence that seems to be possessed by Insects. Neither is it 



