328 GEORGE W. BARTELMEZ. 



a part in the differentiation of the two ends of the shell. I have 

 records of 14 oviducal pigeon eggs which had more albumen cloac- 

 ally of the ovum but no instance of the converse. Many ob- 

 servers have noted for the hen that the pointed end chalaza may 

 belargerthan its mate in the laid egg. Thus: Maitre Jan (1722, 

 p. 16), Leveille (1799, p. 53), Vicqd'Azyr (1805) who says that the 

 chalaza at the pointed end is "ordinairement" greater than the 

 other, as well as Purkinje (1830, p. 18), v. Baer (1828), Berthold 

 (1829) and Coste (1847, p. 293). Occasionally the infundibular 

 chalaza is wanting in the incubated egg or is represented by a small 

 button or cap of denser albumen (cf. Dutrochet (1818), Purkinje, 

 1 830, p. 1 8) . My own observations for these points are tabulated 

 on p. 354. Since any difference in size or distinctness of the 

 chalazae is practically always in favor of the cloacal (pointed end) 

 chalaza, we may say that a difference in the chalazae is a frequent 

 differentiation of the principal axis. 



E. Ligamentum Albuminis. Tredern's original description of 

 the ligamentum albuminis occasioned much interest and contro- 

 versy soon after its publication in 1808 but recent generations 

 seem to have forgotten it entirely. It is familiar to all who 

 have opened fresh eggs at home with a view to strict economy. 

 It should be said that usually it cannot be made out in stale or 

 incubated eggs; there is in fact the same reversal from gel to sol 

 phase in the denser albumen which may occasionally be observed 

 in the chalazae. This tendency is much more marked in the 

 sparrow's than either the hen's or the pigeon's egg so far as my 

 observations go. 



F. The Long Axis of the Ovum. There are two opinions as to 

 the shape of he yolk of the bird's egg. One is the common 

 traditional view, namely, that it is a sphere. Thus Harvey, 

 transcribing his discussion of the yolk largely from Aristotle 

 describes its shape as "perfecte rotundus." Likewise Haller 

 (1758) and Vicq d'Azyr (1805) refer to "la forme spherique du 

 jaune." Pander is one of the careful observers who makes a 

 similar statement and even in Coste's beautiful figures (1847), 

 the outline of the yolk is always a circle. Purkinje himself seems 

 to intimate that the yolk in the laid hen's egg is spherical as his 

 collaborator Valentin (1835) did and as most moderns do, to 



