ZOOLOGY. 539 



wings. There is no part unto which tracheae do not 

 pass, and in this respect completely resemble the arte- 

 ries of other animals. 



3274. The intestine is invariably furnished with an 

 anus, and that too situated quite posteriorly. It is 

 usually expanded into several stomachs and has append- 

 ages, almost as in Fishes, which virtually correspond to 

 the abdomino-salivary or pancreatic gland. 



3275. The salivary ducts open into the mouth, and 

 thus as in the Snails and Kracken, whose similar struc- 

 tures they repeat. 



3276. Whether what have been called the biliary ves- 

 sels are what the name implies, and really convey bile 

 from the fatty body to the intestine, or whether they are 

 lacteal vessels and discharge their fluid near the rectum 

 into the dorsal vessel, does not yet admit of being deter- 

 mined. They have been thought to constitute an urinary 

 apparatus; only certain cysts which occur in connexion with 

 the sexual parts, appear rather to correspond to the latter. 



3277. The nervous system consists, as in the Worms, 

 of two ganglionic ventral chords. 



3278. In the head, the feet again, and probably also 

 wings, undergo repetition. This repetition is nowhere 

 so distinct as in Insects. He who can stiU entertain any 

 doubt of the maxillae being arms, let him resolve to 

 descend into the Insect- world, and he will become in 

 place of a sceptic, a believer. (Ed. 1st, 1811. % 3095.) 

 What have been called manducatory pincers move out- 

 wards as well as the legs, and seize like arms, are only 

 arms. Their gripe takes place in the lateral or hori- 

 zontal direction, and resembles that of scissors or shears. 



3279. Where, moreover, there are three pairs of legs 

 on the thorax, we find also three pairs of maxillae, 

 namely, an upper and lower maxilla, and a labium or 

 inferior lip, which consists of the same parts as the max- 

 illae, only they are united by tegument. 



3280. Where there are five or more pairs of legs on 

 the thorax, as in the Crabs, there also are found as many 

 pairs of maxillae. 



