i8 



from the time of the first feeding great numbers of the eggs of 

 Syngamus were found after they had passed through the fowl's 

 intestines. These eggs passed from perfect worms, which were 

 found attached to the trachea of the chick, killed the same day. 

 Now, the eggs which passed through the chick, and those found 

 about the perfect worms in the trachea, showed no sign of em- 

 bryonic formation. Moreover, we will say that after the exam- 

 ination of many perfect worms removed from the trachea, we 

 have never found the embryo developed within a single egg at 

 that time. In our experience, it takes these eggs not far from 

 three weeks, varying somewhat with the temperature, to mature 

 and bring forth their embryos. We believe Syngami, in which 

 active embryos wer» found within the egg, had been for many 

 days mature, and probably kept in a moist condition, either 

 within the body of the bird or external to the same. The em- 

 bryo of the lung worm of calves (Strongylus micrurus), is fully 

 developed in the egg while in the lungs of the calf. Possibly, 

 reasoning by analogy has had something to do with this opinion 

 heretofore entertained concerning Syngamus. It is evident the 

 eggs, scattered over the ground in the natural way, hatch much 

 quicker during the hot months of summer than later in the sea- 

 son. Indeed, it is quite probable that most of these last perish 

 on account of the cold, without the formation of an embryo. 



DEVELOPMENT OF THE EMBRYO. 



The process of development from the egg is as follows: 

 The yolk undergoes segmentation; that is, becomes divided into 

 2, 4, 8, etc., round masses or spheres, this division being con- 

 tinued until it assumes the mulberry state. The embryo is devel- 

 oped from this around the inner part of the shell, in the form 

 of a circle. Before it emerges the embryo usually coils itself 

 within the egg, like the figure 8, from which it generally comes 

 out head first. The time required for the perfect egg to pass 

 through the different stages, until the embryo issues from it 

 varies, as heretofore stated. On one occasion a few of the em- 

 bryos came forth in seventeen days. The embryo on emerging 

 resembles an Anguillula, but its movements are not as rapid as 

 most of the worms belonging to this order. It is about .01 1 inch 

 in length, and .0005 inch in width at its middle. The posterior 

 half of the body is filled with a fine granular matter. After the 



