Published online by Cambridge University Press: 11 June 2012
The hoatzin (Opisthocomus hoaziri) embryos are of special interest because the species is the only representative of its family and sub-order, and is well known to possess important anatomical features comparable with the bird-like reptiles. Eleven hoazin embryos collected by Dr G. S. Carter in British Guiana have been examined. These range in development from a stage having nine mesoderm segments—equivalent to a fowl embryo of approximately forty hours' incubation—to a single specimen ready to hatch. The earlier embryos resemble the corresponding stages in the development of other birds, but the oldest embryo shows features characteristic of the type and has been dissected. Points in the anatomy of this specimen and their bearing on previous observations on hoatzin embryos are discussed.
This paper was assisted in publication by a grant from the Carnegie Trust for the Universities of Scotland.