Organization of the Teleost Blastoderm

Abstract

The results of expts. performed by the author on the eggs of Fundulus, of those of Luther and Pasteels performed on trout eggs, and of those of Tung and Chang on the eggs of Carassius are compared and discussed critically. The development of all of these forms conforms to the same general pattern; however, minor differences exist in the regulability of the different forms, as shown by defect-expts. The mapping expts. also show some differences between Fundulus and trout eggs. The action of the organizer is similar in Fundulus and trout; the factors, however, organizing the blastoderm as a whole differ in these 2 forms. A physiologic gradient was postulated to exist in the region of the rim of the blastoderm in the case of the trout; no such gradient was demonstrated for Fundulus.