10 WILLIAM PATTEN. 



is a reflex act caused by the stimulation of gustatory organs 

 about the mouth. 



The following experiments show that there are three kinds 

 of these gustatory organs, and that they are situated in the 

 inner and outer mandibles of the second to the fifth pair of 

 appendages. The organs of the first kind are located in the 

 mandibular spines, the second on the smooth concave margin 

 of the inner mandible (fig. 3, g. b.), and the third are scattered 

 over the surface of the mandibles between the spines. 



(1) If the outer surface of one of the mandibles — say the 

 second or third on the right side — be very gently touched with 

 a piece of clam, as small even as the head of a pin, the cha- 

 racteristic chewing movements of that mandible and the corre- 

 sponding leg are alone produced. With care all the appendages 

 on one side, or any number of them, can be made in this way 

 to go through the chewing movements, while the other legs 

 and mandibles remain perfectly quiet. 



(2) If any one mandible, or any combination of them, be 

 amputated, then stimulation of the mouth region with food 

 produces chewing movement of the remaining mandibles and 

 of the corresponding legs, but those legs from which the man- 

 dibles have been removed remain perfectly quiet, even though 

 food be rubbed on the mouth, the rostrum, the soft skin 

 about the base of the legs, or on the proximal part of the 

 leg itself. This proves that the gustatory organs are located 

 in the mandibles alone, and not in or around the mouth, in the 

 rostrum, or in the base of the leg. 



(3) If the stiff spines be shaved off of one or more mandibles 

 and a piece of clam rubbed over the outer anterior surface of 

 the shaved mandibles, either no effect at all is produced, or 

 else feeble movements of the mandibles only, without the leg 

 movement. But the least contact of the clam against the 

 unshaved mandibles produces at once the characteristic man- 

 dible and leg movements ; it makes no difference whether the 

 shaved mandibles are all on one side or not, or what combination 

 may be selected. This proves that a large proportion of the 

 gustatory organs are situated in the mandibular spines; it also 



