Page:Popular Science Monthly Volume 84.djvu/532

This page has been proofread, but needs to be validated.

528

THE POPULAR SCIENCE MONTHLY.

in which the egg undergoes a part of its development within the body of the mother, as it is of oviparous forms in which the eggs are laid before development begins.

The fertilized egg of a star-fish, or frog, or man is not a different individual from the adults of these forms, rather it is a star-fish, a frog, or a human being in the one-celled stage, and thereafter this new being

Figs. 6-9. Successive Stages in the Maturation and Fertilization of the entrance cone (EC) and sperm nucleus (♁N) into the egg. Fig. 6 shows the first maformed by this division; Fig. 8, the second maturation spindle (2d Mat. Sp.) and the in the first cleavage spindle (1st CI. Sp.). (From F. R. Lillie.)

This article is issued from Wikisource. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.