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phagus into the lung, and have in all the chicks carefully exam- 

 ined for that purpose, after dying of the gapes, found several 

 echymosed spots, which looked as though the embryos. had 

 passed through. We have also found them recently united on 

 the outer wall of the oesophagus, one pair being the smallest we 

 ever saw. In dissecting some chickens dying of the gapes, we 

 have found the oesophagus adhering to the lungs, as we believe 

 from the inflammation caused by the passage of the embryos. 

 Both male and female embryos do not develop beyond a certain 

 point until union takes place. After this they pass through the 

 bronchi into the trachea, where they attach themselves to the 

 mucous membrane and attain maturity. 



ANATOMICAL DESCRIPTION. 



We shall not attempt any extended anatomical description of 

 Syngamus. The illustrations accompanying this investigation 

 will show its appearance in the different stages. We will briefly 

 say that the mouth in this Genus is large, circular, and sur- 

 rounded by four outer membranous and six inner chitinous 

 lips. The young worm has eight inner lips, two of which unit- 

 ing with two others reduces the number to six in the adult 

 worm. Within, it is hollowed out, and contains, around the 

 opening to the digestive apparatus, eight lance-like organs, 

 which are supposed to pierce the mucous membrane for extract- 

 ing the blood of its host. 



The Male. — The male has been found coupled on the exter- 

 nal wall of the oesophagus when .035 inch long, and .002 inch 

 wide. At maturity it attains the length of about .24 inch, 

 and a breadth of about .02 inch. The diameter of the head 

 exceeds that of the body, which is round, and its posterior 

 part, containing the genital organs and anus, is united to the 

 vulva of the female by a hood- like organ, with several ray-shaped 

 expansions. Within is seen the digestive and internal genital 

 organs. 



The Female. — The female has been found united with the 

 male on the oesophagus when .055 inch long and .0025 inch in 



