Abstract
By merogony in the broader sense is meant the fertilization and development of egg fragments whether nucleated or not.
By means of the more accurate method of using a mechanical apparatus for microdissection an attempt was made to repeat the work of earlier investigators (O. and R. Hertwig, Boveri, Driesch, Morgan, Loeb, Wilson and others) especially for the purpose of cross-fertilizing egg fragments of the sea-urchin and sand dollar. Owing probably to the lateness of the season the cross-fertilization experiments were unsuccessful.
However, the following results were obtained in the self-fertilization of sea-urchin egg fragments which indicate that the size of the nucleus in the swimming larvæ depends directly upon the initial size of the nucleus in the fertilized egg fragment whereas the size of the larva bears no direct relation either to the size of the nucleus or to the initial amount of cytoplasm in the fertilized egg. Mature eggs were deprived of their nuclei by cutting them out together with a minimum amount of cytoplasm. The nonnucleated fragments were about 415 the size of the entire eggs. These, when fertilized, developed into dwarf larvae of about half the size of the control and with abnormally small nuclei. Other eggs were deprived of more than half of their cytoplasm. These, upon fertilization, developed into dwarf larvae of about half the size of the control but possessed nuclei equal in size to that of the control.
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