332 GEORGE W. BARTELMEZ. 



in Caracas upon 48 eggs laid on coal soot. It was clear that in 

 every case the blunt end had been laid first. 



It was assumed by these writers that the egg is forced out of 

 the uterus in the act of laying by a simple peristalsis and hence 

 that the blunt end passes first down the oviduct. Wickmann 

 (1895) made direct observations upon the laying of eight hens 

 and found that in most cases the blunt end is laid first; one hen 

 however laid five successive eggs with the pointed end first. If 

 the bird is taken some time before an expected laying the egg is 

 always found with the pointed end cloacal, but, as both Purkinje 

 and v. Baer noted, if she is killed near the time of laying either 

 end may be directed toward the vagina. Purkinje suggested 

 that during "labor" the egg was turned about its long axis until 

 its position became "comfortable." He figured the oviduct of a 

 hen with an egg in the "uterus" (Tab. II., Fig. 19), which shows 

 the pointed end so held in a diverticulum of the duct that it is 

 to the right and below the opening of uterus into vagina. Con- 

 sequently the constant peristaltic movements of the duct rotate 

 the egg without tending to drive it into the vagina. Wickmann 

 (1895) was the first to analyze the whole process of laying. 

 He demonstrated in a striking manner that in laying the egg is 

 rotated about its shortest axis so that one end or the other lies 

 opposite the opening into the vagina. Usually it is completely 

 rotated so that the blunt end comes to be cloacal, occasionally 

 there are birds in which the rotation is slight and the pointed end 

 remains cloacal. Now a surprising thing happens. The egg is 

 not simply forced out through the vagina as a mammal is born. 

 The uterus still enveloping the egg is prolapsed through the 

 vagina and the egg is laid without having touched the walls of 

 either vagina or cloaca. Which end is laid first then depends 

 upon chance or the peculiarities of the individual oviduct. 

 There is then nothing to militate against the evidence that the 

 end of the egg corresponding to the pointed end of the shell 

 passes first down the oviduct and we may accordingly refer to 

 this end as the cloacal end of the egg. Taschenberg (1894) 

 states that certain individuals of Corvus frugilegus are apt to 

 lay eggs with the pigment wreath at the pointed end of the shell, 

 instead of the blunt end and that eggs may be found lying 



