Comparative anatomists have been learning to refrain from basing the diagnosis of a species, or the description of the condition of an organ, on the evidence of a single specimen.
After the death of the two anatomists just named, another series of similar descriptions of eight other species was found among their papers, and the whole were published in the Memoires of the French Academy of Sciences in 1733 and 1734.
4 The treatises of the two Bartholinis and Borrichius published at Copenhagen deserve mention if only to record the activity of Danish anatomists in those days.
The most novel feature, and one the importance of which most ornithologists of the present day are fully prepared to admit, is the separation of the class A y es into two great divisions, which from one of the most obvious distinctions they present were called by its author Carinatae' and Ratitae, 2 according as the sternum possesses a keel (crista in the phraseology of many anatomists) or not.
In the course of this evolution there were many cases of arrest or degradation, and one of the most novel of the ideas of Fiirbringer, and one now accepted by not a few anatomists, was that the ratites or ostrich-like birds were not a natural group but a set of stages of arrested development or of partial degradation.