458 PEOF. E. RAT LANKESTER ON 



roach held firmly by the chelicerse, and thus left his chelae free 

 for attack or defence. I observed this on other occasions : a 

 Scorpion, when disturbed feeding, always carries off its prey 

 held in the chelicerse, leaving the chelae free for other uses. 



Mode of ingestion of Food. — The exact mode of bringing the 

 food into the mouth is, naturally enough, very difficult to ob- 

 serve. The mouth of the largest Scorpions existing is a minute 

 aperture not so broad as the shank of an ordinary pin ; and food 

 is drawn into this aperture by a remarkable pumping action of 

 the pharynx, the mechanism of which has been described by 

 Professor Huxley*. The chelicerae, though short, are in all 

 Scorpions provided with exceedingly powerful muscles, and the 

 surfaces corresponding to the cutting-edges of a pair of nippers 

 are not simply cutting-surfaces, but are broad, and fitted rather 

 for crushing than cutting. On one occasion I was able to 

 observe the chelicerse at work, when the Scorpion was feeding 

 upon a young mouse. Each chelicera was protruded, and then 

 withdrawn alternately with its fellow, first the right and then 

 the left, the retraction tending to bring down towards the 

 mouth the soft tissues of the mouse. The range of protrusion 

 and retraction of the chelicera is about equal to its total length. 

 During this process the chelicerae were grasping the intestine 

 and mesentery of the mouse, and the alternate movement of the 

 right and left sides suggested the action of " milking." 



Although these Scorpions always left large portions of the 

 hard substances of their prey unconsumed, and though, from 

 the structure of the mouth, it is clear that no large particles of 

 hard substance can be taken into the alimentary canal, yet it is 

 a fact that a considerable portion of the chitinous cephalic sbield, 

 and dorsal sclerites also, of the Scorpion which fell a victim to 

 one of its fellows was destroyed, and apparently had been 

 consumed by the cannibal. The edge of the remnant of the 

 cephalic shield was notched, as would have been the case had it 

 been crushed by the chelicerae of the attacking Scorpion ; and I 

 am led to the conclusion that, by the aid of the short crushing 

 nippers constituted by the chelicerae, the larger Scorpions may 

 pulverize very dense substances, and subsequently introduce 

 them into the very narrow oral aperture by suction. 



Swelling after Food. — The Scorpion which fed upon its com- 

 panion became as a consequence greatly distended, the soft in- 



* Quart. Journ. Micr. Sci. 1860, p. 250. 



