190 



THE VITAL FUNCTIONS. 



325 



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 struc- 

 ture. 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 (r) ; 

 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 mus- 

 cular apparatus of the gizzard. The smaller teeth, 

 which are set in double lines between each of the 

 larger rows, consist of twelve small triangular teeth 

 in each row. All the teeth contained in this organ 

 are of a brown colour and horny texture, resem- 

 bling tortoise shell. 



The same insect, as we have seen, often exhibits, 

 at different periods of its existence, the greatest con- 



