1818.1 OF THE UNITED STATES. 435' 



and in having tlie hand of the anterior pair of feet, di- 

 lated, spherical, monodactyle, the thumb inflected at 

 base, so as to form a right angle with the hand, com- 

 pressed and obtuse at tip. In the immature state, the 

 spines of the disk of the thorax and abdomen are very 

 acute and prominent, but become more obtuse as the 

 animal advances in age, so that in the full grown subject 

 they are obsolete, often noted only by a hardly eFevated 

 tubercle browner than the shell. They are found in vast 

 numbers in Delaware bay, in the bays of the Newjer- 

 sey coast, and probably much further north. They never 

 attempt to swim, but always crawl slowly on the bottom, 

 the feet always concealed beneath the shell. \^'hen cast 

 ashore by the waves, if they fall on the back, they cannot 

 recover their proper position. Many people feed their 

 hogs upon rheiVi, and it is said that some hogs that roam 

 at large in the districts where they abound, become ac- 

 quainted with the fact of their inability to turn themselves 

 when placed on the back, and when there happens to be 

 a scarcity, with a provident sagacity, they turn as many 

 as they can eat, or as are within their view, before they 

 proceed to satisfy their hunger. This fact with respect 

 to one hog, was related to me on good authority. 



When in'itated they elevate the tail, which is acute at 

 tip, but perfectly harmless. The boatmen make use of 

 the thorax for baling their boats. 



For the reception of her eggs, the female digs a hole 

 in the sand with her feet, of considerable width, and but 

 little depth, usually between high and low water marks. 

 During this season, and for a considerable time previous 

 to the oviposit, she is accompanied by a male, who at- 



