320 A. W. BELLAMY. 



Some days or weeks before extrusion, the egg is suspended 

 from the ovarian membrane in an epithelial sack (Fig. i). This 

 sack, the theca, forms at one region on the egg a narrow stalk, 

 the pedicle, which becomes continuous with the ovarian mem- 

 brane.. Beneath the theca is a layer of follicular cells and beneath 

 this, the vitelline membrane. In the theca are found the blood 

 vessels that supply the egg. 



Table I. gives the location of the pedicle with reference to 



TABLE I. 



Number of Eggs 

 Location of Pedicle. Observed. Per Cent. 



Position A (see Fig. 2) 75 I2 - 2 



Position B 217 35-3 



Position C .259 42.2 



Position D , . 63 10.3 



These results were obtained by taking a number of eggs at random from vari- 

 ous parts of the ovary and determining the location of the pedicie for every egg 

 in each sample. 



the distribution of the pigment on the egg. It will be noted 

 that in approximately eighty per cent, of the cases, the region 

 of attachment (the pedicle) is near or on the boundary between 

 the pigmented and unpigmented regions of the egg (Fig. 2). 



A number of specimens were injected through the conus 

 arteriosus with a lead chromate-starch-gelatin mass 1 and in the 

 great majority of cases only those vessels lying over the un- 

 pigmented hemisphere remained uninjected and could often be 

 traced by the color of the blood remaining in them. In several 

 cases injected vessels were seen to pass a little distance over the 

 unpigmented hemisphere, but in no case was an egg observed 

 where more than a small per cent, of the vessels overlying the 

 yolk were injected (Fig. 3). Several unsuccessful attempts were 

 made to inject the venous system. 



In order to eliminate any error due to the injection mass 

 passing through the capillaries into the veins, several frogs were 

 opened under normal salt solution and the circulation of the 

 blood over the egg determined with the aid of the binocular 

 microscope. In every case where the movement of corpuscles 

 over the pigmented hemisphere could be seen, the circulation 



1 Guyer (2d edition, page 84). The mass was made up in a i per cent, uncooked 

 starch suspension, warmed and well stirred immediately before the injection was 

 made. 



