L 



of the Mole-crickd. 4 1 5 



zartl, wlille ihe sides form two enormous caeca, which ascend 

 obliquely outwards on each side of the gizzard. 



As the muscular compression of the gizzard must necessarily 

 have a tendency to force a part of any expressed fluid back 

 into the oesophagus, we may expect this organ to be so con- 

 structed as to prevent such an effisct; and it is probably for 

 this purpose that its upper part is furnished with several 

 projecting papillae, each terminating in a small horny particle ; 

 which, like the sesamoid particles in the semilunar valves of 

 the human aorta, may serve to complete the valvular action 

 of the papillee to which they are attached. 



The caeca which have been above described are traversed 

 longitudinally by several very broad duplicatures of their in- 

 ternal membrane; and judging from their usual contents, 

 these appendages of the intestine are destined to receive an(l 

 to perfect the digestion of those particles of food from which 

 the gizzard has pressed out the liquid contents; and while, 

 by means of the membranous folds already described, the ex- 

 pressed fluid is conveyed immediately into the mouth of the 

 intestinal canal that passes from the general caecal cavity, the 

 caeca themselves receive the solid compi-essed particles which 

 are forced out laterally at the extremities of those two divi- 

 sions of the gizzard, which, having no membranous fold at- 

 tached to them, leaves thus a vacant interval for the passao-e 

 of the undigested mass. That this opinion is correct may be 

 presumed, not only from the very mechanism of the parts, but 

 from the state of the contents of the cesca, which are of a less 

 crude character than the contents of the crop, and of a more 

 crude character than the contents of the portion of intestine 

 immediately beyond them. A strong confirmation of the fore- 

 going opinion is obtained from a comparison of this part of 

 the anatomy of the mole-cricket with that of the correspond- 

 ing part in the ostrich ; the stomach of which bird, acting like 

 a gizzard by means of numerous pebbles which it takes into 

 that organ, is aided by two enormous caeca, which, though 

 they are not immediately in contact with the stomach, are not 

 far removed from it; and, like the stomach, contain numerous 

 pebbles, which are both smaller and smoother than those of 

 the stomach itself, as being only destined to act on food al- 

 ready partially digested. The analogy on which I have just 

 insisted, is strengthened by the fact that there are very laroe 

 duplicatures of the internal coat of the caeca of the ostrich, as 

 in the corresponding parts of the mole-cricket. I either there- 

 fore misunderstand or cannot agree with M. Marcel de Serres, 

 (the author of a very interesting paper oil the Intestinal Canal 

 of Insects, published in the 76tli volume of the Journal dc 



Physique) ,- 



