Abstract
The present author, in his previous paper, reported that the embryo of the “New Additional Crescent” silkworm, homozygous for the N gene, died in late embryonal stage without showing. any blastokinesis during its embryonal.development.
Since then further studies were made in order to ascertain the anatomical characteristics of the abnormal embryo of both N and Ca strains, with the following results : -
Limits of the multiple effects of the N or Ca gene.
The appendages, bristles, stigmata, and tracheae of the N/N embryo in the 1st to 8th or 9th body segment were found to have the form of the thoracic segments of normal embryo (Figs. 1, 3), whereas the embryo of the Ca/Ca strain had only rudimentary stigmata and tracheae, without any abdominal appendages (Figs. 2, 4) -facts pointing to possibility of numerous interesting studies, particularly in connection with the multiple effects of gene, blastokinesis of the embryo, lethality as the result of abnormal development of embryo, etc.
