U THE AMERICAN MONTHLY [Jan. 



border the gall-bladder can be seen. By drawing the 

 liver aside, \\\q gullft can be seen doraally to the heart; 

 the stomach is a fusiform enlargement in the course of the 

 alimentary tube which passes insensibly into i\\e smaU 

 intestine. The latter is somewhat longer than the body 



;■'■ cavity and hence is winding in its course; the mesentery 

 , can be seen clearly on its dorsal side and portal vessels 2iX^ 

 i recognizable. At the upper end of the small intes- 

 tine you can find the bile-duct running into it froin the 

 j^all-bladder; and in the mesentery near by there is a dif- 

 : fused mass of pancreatic tissue^ whose ducts open into 



' thci small intestine, '^h.^ large interline directly follows 



. the small intestine, is not sub-divided into parts but has 

 the form of a short rectum passing directly to the 



; 1 ; . claafa. 



' ^8. The Lungs are a pair of elongate, slender, thin- 

 ^' walled sacks; biirid posteriorly, they come together in 

 front and above the heart where they open inio a passage 

 which leads to the ^/i?///^ already noted in the hinder part 

 ■ of the mouth chamber just behind the tongue. In the 

 higher vertebrates this air tube {trachaea) is lined, with 

 cartilage, but it does not appear to be so in the sala- 

 manderi The pass^ige can be demonstrated by passing 

 a guarded bristle down through the glottis. The lungs 

 should be cut open to show that the interior is a very 

 simple sack with only a beginning of that elaborate sub- 

 ' division into spaces found in the mammal. The wall* 

 '^^•^ are reddish, tills indicates the presence of blood vessels 

 • 'in Contrast with the colorless wall of the swim bladder 

 of the smelt; but to prove that the wall is vascular mount 

 a thin film of it and examine with the compound micro- 

 scope. Do you find any blood corpuscles there? 



[This and the reptilian lung are simple conditions of the 

 lung of which the bird and mammal lung are very highly 

 specialized conditions. The circulation and respiration 



