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the examination of many perfect worms removed from the tra- 

 chea, 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 were 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 

 embryo 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 the 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, it becomes divided into 

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

 ued 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 with- 

 in the egg, like a 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 embryos 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 .011 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 embryos 

 have been in water a few days they moult, losing about .0005 

 inch in length; their tails are also more blunt. Sometimes they 

 pass through the first moult while coming out of the &gg, leav- 

 ing the old skin within. 



