78 



COMPARATIVE ZOOLOGY. 



the Lobster, have a short gullet leading to a large cav- 

 ity, situated in the front of the animal, which is a giz- 

 zard, rather than 

 stomach, as it has 

 thick muscular 

 walls armed with 

 teeth. A well- 

 marked constric- 

 tion separates this 

 organ from the in- 

 testine. The liver 

 is highly devel- 

 oped; instead of 

 numerous folli- 

 cles, there is a 

 large bilaterally 

 symmetrical or- 

 gan, divided into 

 three lobes on each 

 side, pouring its 

 secretion into the 

 upper part of the 

 intestine, which is 

 the true stomach. 

 J'Among Insects, 

 there is great vari- 

 ation in the form 

 and length of the 



PIG. 40. Anatomy of a Caterpillar: cj, h, oesophagus; h, i mi /? -n 



i, stomach ; k, hepatic vessels ; I, m, intestine ; q, r, sal- Canal. 1 lie lOllOW- 



ivary glands; p, salivary duct; a, 6, c, longitudinal _ nrf . Q __ n p _ 



tracheal trunks; d, e, air-tubes distributed to the vis- 11J & P* 11 1& tcin & en ' 



cera; /, fat-mass; v, x, y, silk-secretors ; z, their ex- grally be distil.l- 

 cretory ducts, terminating in t, the spinneret, or fu- * 



wins. guished : gullet, 



crop, gizzard, stomach, and large and small intestines, with 

 many glandular appendages. The crop, gizzard, and large 

 intestine are sometimes absent, especially in the carnivorous 



