Mr Borradaile, Mouth-parts of certain Decapod Crustaceans 479 



parts. Possibly it feeds, not, as Hapalocarcinus does, only upon 

 the very minute organisms which make up the nannoplankton, 

 but also upon suspended particles of greater size and toughness. 

 Or it may be that it uses the chelae for seizing food, though I have 

 not seen it do this. Another case of the same kind would seem to 

 be presented by the prawn Paratypton, which was found by 

 Potts to live in a coral gall somewhat in the same way as Hapalo- 

 carcinus. Details of its habits are not known, but it does not at 

 present appear likely that it can obtain any but finely divided 

 food. Yet its jaws show neither any provision for gathering such 

 food nor any marked reduction in masticatory structures. 



All these organisms deserve a good deal more investigation than 

 they have received. 



VOL. XX. PART IV. 



31 



