1) Many auto- and allotetraploids and diploid-tetraploid mosaics of newts were produced by treating the eggs of two species of newts, Triturus pyrrhogaster and Triturus ensicauda, by ultrasonic waves. When the temperature of the water around the eggs in the test tube was raised at 39°C, which required 3-5 minutes by the action of ultrasonic waves, the latter were effective in inducing tetraploid and diploid-tetraploid mosaics.
2) All the autotetraploids produced from Triturus pyrrhogaster or Triturus ensicauda had a same vital power as the control (diploid) until their metamorphosis, on the contrary after the landing, they could not complete their metamorphosis and died within half a year wholly.
The allotetraploids of Triturus pyrrhogaster and Triturus ensicauda could complete their metamorphosis and have a same vital power as the controls approximately. Especially the allotetraploids of Triturus ensicauda ♀×Triturus pyrrhogaster ♂ were stronger in vital power.
3) Among most of the organs of diploid newts of the four mating, Triturus pyrrhogaster ♀×Triturus pyrrhogaster ♂, Triturus ensicauda ♀×Triturus ensicauda ♂, Triturus pyrrhogaster ♀×Triturus ensicauda ♂, Triturus ensicauda ♀×Triturus pyrrhogaster ♂, especially conspicuous differences were not seen, but the vertabra of Triturus ensicauda and hybrid diploids produced from Triturus ensicauda were observed as stronger and their ossification were observed as more prograssive.
On tetraploids, the same facts as the above can be stated, too, but the ossification of tetraploids was generally seemed to be delayed a little as compared with that of the controls.
4) All the cells and cell nuclei consisted of every organs of tetraploids were larger than twice of diploid one in volume and less in number. Then the constitution of tetraploid organs was simple in general. Especially, all the gland tissues (gastric glands, lacrimal glands, salivary glands, thyroid gland, hypophysis etc.) of tetraploids were very simple in structure and very few in number.
5) The sex ratio made clear in tetraploid newts up to date, was 6 females and 4 males in 14 Triturus pyrrhogaster ♀×Triturus pyrrhogaster ♂, 1 female in 1 Triturus ensicauda ♀×Triturus ensicauda ♂, 10 females and 7 males in 18 Triturus pyrrhogaster ♀× Triturus ensicauda ♂, 3 females and 2 males in 5 Triturus ensicauda ♀×Triturus pyrrhogaster ♂.