III. Additional observations on the development of apteryx

Abstract

Since communicating my previous observations on this subject to the Royal Society (1), I have received from the collector (R. Henry) to whom I owe most of my material, three embryos of Apteryx austrlis , which fill important gaps in the series of developmental stages formerly studied, and serve to correct one or two erroneous conclusions to which I was led by having, in so many cases, only a single specimen of each stage. The youngest of the three embryos is as nearly as possible intermediate in age between Stages E and F of my former paper: I shall speak of it as Stage E'. The second is slightly more advanced than Stage F, and will be called F'.