06 



cvr.l embryo destitiito of n Mr.stocoelr , v-hi<"h rc.y be cr.llPd 

 r. noriila strpr. The cells of the sep-'-ertinp epr are all 

 alike ir^ ctriicture and nearly equal in size; so that they are 

 not disti- ruishable into r^ri'itive ectoder- and Tinitive 

 endoder:-, vrhich ir. the car.e in fcrrs v;hero a definite de- 

 lariration takes rlace, as is so beautifully shov/n in 

 Liriore and Gerypnia, and in sneeios where cellular inf^res- 

 sion occurs as in Stprctcca and Clytia for exa-nle. Fir- 

 ure? ?5 to 50 illustrate the u-ifor-ity of the cells, ard 

 the solid character of the efP. curinp seprentatio:- . In 

 I'ipure 27 a sDace exists between the blastcreres near ere 

 end of the epp , but this is not to be regarded ar a true 

 cleavage cavity. The next figure shows three of these false 

 cleavage cavities. They occur only cccasiorally. As 

 stated before rost of the epps are entirely rclid. 



About the tire the irregular rass of seg^entinp blasto- 

 neres is retarcrnhcsed into the oval rrrbryc, the cell boun- 

 daries are lest for a short tire and a syncytiur is f erred. 

 This syncytial structure ir crowded with yolk pranules and 



