70 



MR. L. A. BORRADAILE ON THE 



maxillipeds are also capable by the same action of scooping up 

 food and unaided conveying it to the second maxillipeds, between 

 which they sometimes thrust it with their tips. During these 

 processes the basket which has been mentioned seems to serve 

 the purpose of keeping the food under control till it has been 

 seized by the second maxillipeds. These are very important 

 organs, and play an indispensable part in passing food to the 

 mandibles. The animal can still feed if the legs and third 

 maxillipeds have been removed, but if all the other organs be 

 left and the second maxillipeds cut away it is apparently incapable 

 of taking food. The second maxillipeds have three principal 

 movements. In one, the broad flaps in which they end open 

 downwards like a pair of doors, and with their stout fringes 

 gather up the food ; in another they rotate in the horizontal plane 

 to and from the middle line of the body and thus narrow or 

 widen the gap between them ; in the third the bent distal part of 

 the limbs tends to straighten so as to brush forward any object 

 which lies between them. Frequently these movements are 

 combined. Once the food is past the portals formed by the 

 second maxillipeds its course is hard to trace, but the following 

 seems to be its fate. If it be small in quantity and finely divided, 

 or very soft, it is abandoned to the action of the maxillules, by 

 whose strong, fringed laciniae it is swept forwards and probably 

 caused to enter the mouth through the slit between the para- 

 gnatha. The lacinire can be moved separately, and the difference 

 between them, in shape and in the kind of bristles they bear, 

 probably corresponds to some difference in function. If the food 

 be bulky or tough, the second maxillipeds assist the maxillules in 

 brushing it forwards towards the incisor processes. The action 

 of these latter is not so much a cutting as a process of tucking 

 the food into the lip-chamber by first backing outwards and then 

 moving inwards and rotating upwards. No doubt, during this 

 the food generally undergoes some tearing, and when the mass 

 of it is large, pieces have to be torn from it before they can be 

 swallowed. The palp does not appear to take any mechanical 

 part in the process of feeding. If it has a sensory function this 

 is probably not of great importance, for the organ is present and 

 absent in closely related genera in many cases among Carides. 

 Finally, to enter the gullet, the food must pass between the 

 molar processes and doubtless be pounded by them as it goes. 

 Their concave ends are usually found to be clogged with a pasty 

 matter. They must clo their work very quickly, for the move- 

 ment of the mandibles, as judged by that of the incisor processes, 

 ceases very soon after the food leaves the latter. How swallowing 

 takes place is not clear. Parker and Mocquard suggest that the 

 food of Decapod crustaceans is caused to pass up the gullet by 

 suction from the crop (stomach), but, as I have shown elsewhere *, 

 the case of the land hermit-crabs of the genus Ccenobita throws 



* Gardiner's ' Fauna of the Maldives,' vol. i. p. 79 (1901). 



