34 



CURL. 



Fig. 1. — Stomach of Hydrocorax hydrocorax show- 

 ing : A, deciduous membrane almost 

 ready to be cast off (note its separa- 

 tion) : B, stomach before the prepara- 

 tory separation has taken place. 



is 50 millimeters in diameter, and when filled with food twice as 

 large, it can readily be seen that when the lining membrane is cast ofE 



entire, it forms a sac with 

 the two openings close to- 

 gether at the top. 



In a stomach where the 

 sac-like lining is abont to be 

 cast off, it separates from 

 the entire surface of the 

 stomach before its upper, 

 neck-like portion separates 

 finally around the pyloric 

 opening, at which point it 

 thins down rapidly and dis- 

 appears just above the 

 sphincter muscle. On the 

 other hand, in a specimen 

 where the lining membrane 

 is in an earlier stage of for- 

 mation (i. e., soon after the 

 last one has been cast off), 

 no macroscopical separation can be demonstrated, although microscop- 

 ically the line of future separation is well seen. 



On section the stomach is found to have an external serous coat, a 

 thick muscular coat, and a mucous lining. There is nothing peculiar 

 about the serous and muscular layers. The mucous membrane shows 

 closely studded, long, iiager-like villi which have tubular glands at their 

 bases and are covered by a single layer of cells with large nuclei. 



When the deciduous membrane is just beginning to form, the spaces 

 between the villi are filled with colloid-appearing material which stains 

 a bright orange-yellow by the Van Gieson method. A little later this 

 layer becomes thicker and lies as a continuous coat over the entire inside 

 of the stomach. Before it is ready to be thrown off, it becomes in fact, 

 thicker than the mucosa itself. ^ The deciduous membrane is of homo- 

 geneous structure, is quite tough, and on its miicous-membrane side is 

 an accurate cast of the rugs of the stomach. It seems cei-tain that this 

 layer, which is so peculiarly cast off, is formed by secretion from the 

 glands of the stomach and after reaching its full thiclaiess, separates 

 spontaneously, leaving the glands to begin at once the formation of a 

 new sac. 



The intestine is from 920 to 950 millimeters in length and, having 

 no caecum, is not clearly divisible into large and small portions except 

 possibly by its structure when examined from within. The mucous 



