Having been occupied for some time with a detailed and close examination of the specimens belonging to this group of Ant-eaters which form part of our collections, I have been led to observe certain points in the external form and in the structure of the skeletons which appear to me to be not without interest as these facts throw a clearer light upon the classification of these curious creatures. I wish to give a short exposition of them before proceeding to an enumeration of our individuals. The observations which I have been able to make have been repeatedly confirmed and controlled by myself thanks to our unequaled and nearly complete collection of stuffed specimens and individuals in spirits, of skeletons and skulls, embracing all the species hitherto known.