Habits of the Crab 209 



genus Gelasimus. Thus according to the observations 

 of Prof- S. I. Smith, quoted by Stebbing (Recent 

 Malacostraca pp. 89-90), the American species. 

 Gelasimus pugilator Latreille, is a vegetarian and feeds 

 upon the minute algae which grow upon the moist sand. 

 The males of this species have one of the chelipeds 

 enormously enlarged, and in feeding they use only the 

 small cheliped, with the claw of which they pick up the 

 bits of algae very daintily ; the females use indifferently 

 either of their small chelipeds for this purpose. Thus 

 in Gelasimus pugilator bits of algae are picked out 

 from the sand, whereas in the present species the food 

 particles are strained off from the sand. 

 (c) Methods of taking food from sand are known also in 

 other animals. Some Annelids, e.g., Arenicola, take 

 quantities of sea-sand into their digestive tracts for the 

 sake of the organic particles and small organisms which 

 it contains, i.e. they literally eat the sand for the nourish- 

 ment which it contains. 

 Hence there can be but little doubt that the process described 



above is an interesting method by means of which this little crab 



obtains its nourishment. 



My thanks are due to Mr. K. H. Barnard. M.A. for kindly 



determining the species. 



