PHYSIOLOGY OF REPRODUCTION IN DOMESTIC FOWL. 1 55 



partly or entirely enclosed by peritoneum. In several instances 

 two eggs or an egg and a bunch of membranes were walled off 

 together. The last line of the figure shows collections of empty 

 membranes enclosed in peritoneum. These peritoneal covered 

 masses were attached by suspending strings,or folds of peritoneum. 

 The large mass at the right end of this line contains a very large 

 number of these empty membranes. A larger view of it is 

 shown in Fig. 2. The second line from the bottom of Fig. i 

 shows collapsed empty egg membranes of which some are single 

 and some two or three tightly packed together. The three top 

 lines of the figure show eggs in various stages of resorption. One 

 was a normal fresh egg in a single egg membrane. Ten had 

 evidently been normal eggs but at the time of autopsy they con- 

 tained a homogeneous mixture of yolk and albumen which had 

 lost the gelatinous character of fresh egg albumen. Each of 

 these eggs was enclosed in a single egg membrane. The other 

 four eggs were double eggs. These eggs were much like the double 

 eggs {ovum in ovo) described by Parker (1906), Patterson (191 1) 

 and by many other writers. (The appended bibliography is 

 supplementary to the one given by Parker 1906.) 



The eggs of this sort described in the literature had all been 

 laid. Most of them have had shell on one or both of the con- 

 centric components. The double eggs found in the body cavity 

 of this Rhode Island Red hen had no shell on either the enclosed 

 or enclosing egg. The nature of the contents of the double eggs 

 differed in each of the four cases. In one both enclosed and 

 enclosing egg contained yolk. The yolk and albumen of the 

 enclosing egg were somewhat mixed, although they did not yet 

 constitute a homogeneous fluid. In fact the currents or streams 

 of yolk could be seen in the clear albumen through the semitrans- 

 parent egg membrane. The yolk and albumen of the enclosed 

 egg were still more distinct although the yolk membrane had 

 already ruptured. The enclosed egg was about the size of the 

 normal egg and the enclosing egg (the third egg in the top line) 

 was the largest egg found in the body cavity. A second double 

 egg was composed of a normal sized enclosed egg which had 

 apparently contained the normal egg parts. The contents had, 

 however, been reduced to a homogeneous brownish-yellow liquid 



