206 R. Bigalke 



the animals withdraw into their burrows, but immediately on emerg- 

 ing from their burrows they are erected. It is evident then that the 

 orbits are protective in function, and prevent the eyes from scrap 

 ing the sides of the burrow when the animal withdraws into it. 



When they have come out of their burrows the little animals 

 move slowly sideways, and if an individual be observed closely it 

 will be noted that the che lipeds are actively moving; the basa 

 portions of the third maxillipedes, which, when the animal is at 

 rest, lie flat against the body and meet in the middle line, are now 

 seen to have a small gap between them in the middle line and to 

 slope away at an angle from the body, a groove being thus formed 

 between them. With he claws of the che lipeds wet sand is scraped 

 on to the lower portion of this groove and passed forwards, and 

 presently a little ball of sand appears at the mouth region, looking 

 as though the animal were Mowing sand bubbles. When this 

 globule has reached a diameter of about Ys of an inch or less, 

 according to the size of the animal, it is nipped off quickly with 

 the claw of one of the che lipeds, passed under the second and 

 third pereipods of the same side, and pushed away behind the 

 animal with the fourth and fifth pereiopods of the same side. These 

 globules of sand are produced at the rate of about 25 per minute. 

 In scraping up the wet sand both che lipeds are used, and in 

 nipping off the globule the same che liped may be used a number 

 of times in succession and then the other one, or each may be used 

 alternately for a number of times. While performing the process 

 the crabs stand with the body laised off the ground, but every now 

 and then they sit down with the posteriot margin of the body rest- 

 mg on the ground just for a few seconds, as though to rest the 

 body, It is the accumulation of these globules of sand prepared 

 by thousands of the little animals that gives a portion of the beach 

 the gravelly appearance mentioned above. 



In performing the process it appears that the animal does not 

 move more than about 6 inches from its burrow, and if a neighbour 

 intrudes on its little pathway he is vigorously attacked, though in 

 none of the cases observed was either of the pugilists harmed. 

 Occasionally some of them lose themselves owing to the fact that 



