THE AXIS OF THE EMBRYO. 



furrow indicated on the paper oriented as in the earlier experi- 

 ments. 



On July 12, six days afterward, during which time the dish 

 containing the eggs was not moved, the axis of the embryo was 

 observed, and its direction indicated as before. The result is 



FIG. V. 



seen in Fig. V. Of the fourteen eggs only two show coinci- 

 dence of the first cleavage furrow with the embryonic axis 

 (Fig. V, 5, n). 



Similar experiments with the eggs of Amia have been made 

 by Eycleshymer, '96. 1 Observations were made on three sets 

 of eggs and the results are given in Fig. VI. 



Twenty eggs developed normal embryos, and two showed 

 coincidence of the first plane of cleavage with the axis of the 

 embryo (Fig. VI, 2 and 6). The following is quoted: "The 

 egg is oval in profile view, measuring in its longest diameter, 

 including the membrane, 2.5 to 3 mm.; in its shortest, 2 to 

 2.5 mm. The freshly deposited egg is firmly fixed to the 

 object with which it first comes in contact by means of the 

 threads of the villous layer, which are elongated over the lower 

 hemisphere of the egg-membrane. 



The eggs still attached to blades of grass or rootlets are 

 placed in shallow watch-glasses and held in position by weight- 

 ing with small pebbles. The watch-glasses are then placed 



1 Joiirn, of Morph., vol. xii, p. 344. 



