Transmission of Homoiogenetic Induction in Presumptive Ectoderm of Newt Embryo.

Using newt, Cynops pyrrhogaster, embryos, the production and/or transmission of a homoiogenetic effect of the induction within a presumptive ectoderm was investigated. The primary inductor was the swimbladder of a crucian carp, Caracius auratus. In the first experiment, a piece of presumptive ectoderm was isolated from an early gastrula and one-third of its inner surface was placed in contact with the swimbladder for 30 min.

DIFFERENTIATION OF PARTIALLY MESODERMALIZED ECTODERM; HOMOIOGENETIC AND HETEROGENETIC INDUCTION BY PRIMARILY INDUCED PART OF THE ECTODERM.

Using embryos of the Japanese newt, Cynops pyrrhogaster, homoiogenetic and heterogenetic induction were investigated in the partially mesodermaelzed presumptive ectoderm. Half of the isolated presumptive ectoderm was placed in contact with the swimbladder of the crucian carp, Carasius auratus, for 15 or 60 min, while the other half was stained with Nile blue sulfate at the same time. The distribution of the stained cells in the tissues evoked in the explants was examined after cultivation for 10 days.

VEGETALIZATION OF PRESUMPTIVE ECTODERM OF NEWT GASTRULAE IN A TRANSFILTER EXPERIMENT WITH FISH SWIMBLADDER AS THE INDUCTOR.

The diffusibility of the vegetalizing factor was examined by a transfilter culture using an ethanol-fixed swimbladder of the crucian carp (Carassius auratus) as the inductor and presumptive ectoderm from gastrulae of Cynops pyrrhogaster as the responding tissue. Nucleopore filters, about 12-14 μm thick, with nominal pore sizes of 0.05, 0.

STAGING OF NEWT BLASTULA EMBRYOS AND FIRST APPEARANCE OF PRIMARY MESODERMAL COMPETENCE.

Using the swimbladder of the crusian carp (Carrasius auratus) as an inductor, the first appearance of mesodermal competence in the presumptive ectoderm of the newt (Triturus pyrrhogaster) blastula was investigated. The time course of embryonic development before the gastrula stage was determined by counting the number of surface cells on a 0.25 mm line at the animal pole.