354 GEORGE W. BARTELMEZ. 



chalazae unattached and in these there is no chalazal axis. 

 The two chalazae are frequently unequal in size or form, as was 

 said above (p. 327). Thus only the cloacal chalaza may be 

 forked at the end, or it may be merely longer or stouter than the 

 infundibular one. On the other hand, the two may be indistin- 

 guishable. The following table shows the absolute and relative 

 frequencies with which these were encountered and it gives also 

 the frequencies of various kinds of abnormal eggs. 



Total number of eggs recorded with complete data. . . (447)100 per cent. 



Infertile or abnormally developed eggs (39) 9 per cent. 



Eggs lacking the long axis (19) 4 per cent. 



Eggs lacking the chalazal axis (14) 3 per cent. 



Chalazae equal in size and shape (127) 28 per cent. 



Cloacal chalaza recorded greater than other ( 2 59) 5 per cent. 



Infundibular chalaza absent but button of chalaziferous 



albumen present (69) 15 per cent. 



Girdle of Vicq d'Azyr present (2) 0.4 per cent. 



Double-yolked eggs (2) 0.4 per cent. 



It should be said that of the 19 cases which had no long axis 

 5 were either infertile or had abnormal embryos. This was 

 true of 3 which lacked the chalazal axis. On the other hand, 

 irregular chalazae are much more frequent. Patterson (1909) 

 reported 8 per cent, such eggs, including those which lacked 

 one chalaza. If we make a similar category in the present 

 records, including those eggs which have only a button at the 

 infundibular end of the long axis and those with accessory and 

 unattached chalazae we get 91 cases (20 per cent.). I have 

 records of only two eggs which had both long and chalazal axes 

 abnormal; approximate measurements of the axis angle can be 

 made in 98 per cent, of normal pigeons' eggs and accurate 

 measurements can be made in 88 per cent, of cases. When the 

 long and chalazal axes do not coincide, as occurs in 2 per cent, 

 of the eggs, they may diverge from 4 to 20, very rarely more. 

 Most of these were otherwise normal and it should be borne in 

 mind that the same is true of most eggs which lack long or 

 chalazal axes. This emphasizes the fact that this relation is an 

 effect, not a cause; it is simply the morphological expression of 

 the presence of certain axes of bilaterality. The embryo may 

 develop normally whether this expression is perfect or not. 



We may say then, that in the pigeon's egg the chalazae vary 



