A Sexual Transformation of the Osseus Bulla in Duck Embryos following Administration of Estrogen

Publisher Website
Google Scholar
Abstract
The osseus bulla is a [male] sex character found in certain spp. of ducks which is frequently used in sexing embryos. It is located on the trachea at the point of bifurcation to form the bronchi. It is asymmetrical, growing out laterally and anteriorly on the side of the left bronchus, accounting for the fact that the lower larynx is larger in [male] [male] than in [female] [female]- When white Pekin embryos treated with 2.50 mg. of hexestrol on the 4th day of incubation and killed on the 25th were examined, the trachae were [female] in type. However, those of controls clearly displayed sexual dimorphism. Embryos similarly injected on the 6th, 8th, 9th or 10th day and killed between 19th and 28th day displayed trachae of definitely [female] type and sexes could not be distinguished by examination of wi ad-pipe alone. When injns. were made on the 12th day, [male] [male] could be identified though the osseus bulla was not typically [male] In [male] [male] treated on the 14th day, it was larger and more [male] -like, whereas in those treated on the 16th it revealed only slight modifications. Those ^injected on 18th day ware unaffected. These results indicate that the osseus bulla undergoes feminization following injn. of hexestrol during early embryonic life and therefore cannot be used as a criterion of the genetic sex of embryos in expts. employing this hormone.