174 ' [January, 



Rapid changes now take place in the outline of the yolk-sac, 

 appearing as if broken at one side, and sometimes at both sides, as 

 the amniotic sac is being folded in from it, in 38 hours there is a fold 

 from the other side, and in 40 hours these two masses unite, when it 

 bears a fanciful resemblance to a cottage loaf. 



The outer mass of yolk is now composed of spherules containing 

 granules, very irregular in outline, and broken as it were on each side, 

 continually changing its shape, with a flowing and pressing motion on 

 the inner sac. In 44 hours, central mass melting into one rounder 

 mass, and in 48 hours, the outer mass or annulus of yolk, closing round 

 still more, with a slender scroll just traceable at one side of the 

 inner sac. 



In 54 hours, this scroll has developed a funiculus, connecting the 

 embryo with the annulus of yolk ; the inner sac is now distinct enough 

 with the oval outline of the esrs:. 



The development of the embryo now proceeds in this inner sac, 

 the ends curving twowards the funiculus till it comes to resemble 

 somewhat the section of an agaric. In 60 hours, it is curved still more. 



In 72 hours, it may be compared to the capital of an Ionic column ; 

 it now becomes flattened ventrally with the faintest indication of 

 segments forming at this part. A clear concentric line is now left 

 between the developing embryo and the amniotic sac. The yolk- 

 granules are now arranged in loose masses in the annulus, so much 

 detached, in some places, as to leave a clear space through which you 

 could see the distal chorion. Now about 80 hours since the eggs were 

 deposited. 



"We have now reached the Fourth day of incubation. Up to this 

 time, great changes had taken place in the outer mass or annulus, but, 

 after this, it is subject to but little change, except in diminution of 

 bulk, as the yolk granules are absorbed by the growing and contin- 

 ually changing embryo. Towards the close of the fourth day, the 

 embryo was observed to have increased in bulk with a peculiar bladdery 

 appearance, and a clear fissure in funiculus. Three hours later, this 

 clear space becoming obliterated, as also those in annulus noticed above. 

 The yolk-granules becoming denser, especially at micropylar end where 

 the annulus is broadest, and the spherules closer. At the close of this 

 day, the ventral segments becoming better defined, though much 

 obscured by yolk-granules of annulus. 



Fifth day, at 7 a.m. — The scrolls formed by the embryo losing 

 their double character, being so much obscured at head end (in all 

 cases towards the micropyle), that the tail comes to look more like a 



