DIGESTIVE ORGANS OF INSECTS. 215 



tion of the body, lies underneath the gizzard, 

 divides it apparently into two sacs. The intes- 

 tinal canal is pretty uniform in its diameter, re- 

 ceives in its course a great number of hepatic 

 vessels (h h) by separate openings, and after 

 making one convolution, is slightly constricted at 

 N : it is then dilated into a colon (c), on the coats 

 of which the longitudinal muscular bands are 

 very distinctly seen. Fig. 322 is a magnified 

 view of the gizzard laid open, to show its internal 

 structure. It is furnished with six longitudinal 

 rows of large teeth, and six intermediate double 

 rows of smaller teeth ; the total number of teeth 

 being 270. One of the rows of large teeth is 

 seen, detached, and still more magnified, in Fig. 

 323 : it contains at the upper part, five small 

 hooked teeth (f), succeeded below by four broad 

 teeth (d), consisting of quadrangular plates, and 

 twelve tricuspid teeth (t) ; that is, teeth having 

 three cusps, or points at their edges. Fig. 324 

 shows the profile of one of these teeth ; a, being 

 the sharp point by which the anterior acute angle 

 of the base terminates. Fig. 325 exhibits the 

 base of the same tooth seen from below ; e, e, e, 

 being the three cusps, and m, the triangular 

 hollow space for the insertion of the muscles 

 which move them, and which compose part of 

 the muscular apparatus of the gizzard. The 

 smaller teeth, which are set in double lines 

 between each of the larger rows, consist of twelve 



