FAM. 1. ECHIDNIDAE.--This family contains two genera, of which _Echidna_ is the older and much the better known. The skin is abundantly covered with spines, with which are mingled hairs. The snout is tapering, the tail rudimentary, and the fingers and toes five in number. The spur and gland upon the calcaneum are smaller than in _Ornithorhynchus_. The claws are very strong, serving to tear open the ants' nests, upon the inhabitants of which the Echidna feeds, licking them up with a long extensile tongue like that of _Myrmecophaga_. In relation to this habit the salivary glands are enormously developed, and indeed the animal has been confounded with _Myrmecophaga_,[59] as the vernacular name "Australian Anteater" exemplifies. {111} In the skull the Echidna differs from _Ornithorhynchus_ in the greater extension backwards of the palatines, and the larger size of the pterygoids. The extent and relations of these bones to each other is not at all unlike that which obtains in many Whales. The premaxillae show traces of the same divergence followed by convergence of their ends that is seen in the Platypus. There are only sixteen pairs of ribs, and either three or four lumbar vertebrae. _Echidna_ has no trace of teeth, and there are no horny pads which take their place; the mouth is as edentulous as in the true American Anteaters. The brain (Fig. 53) is marked by sulci, contrary to what we find in _Ornithorhynchus_. The genus has been divided into three species, but it is doubtful whether more than one can be allowed, which ranges from Australia through the Papuan region. While there is but one species of true _Echidna_, a New Guinea species must clearly be referred to a distinct genus _Proechidna_.[60] This animal is to be distinguished by the fact that there are usually but three toes on each foot. But there are copious rudiments of the other phalanges, upon which claws are sometimes developed. The beak is curved downwards, and the back is rather arched; the whole animal has the most singular likeness to an Elephant! The ribs are increased by one pair, and there are four lumbar vertebrae. The one species is named _P. bruijnii_. The Hon. W. Rothschild[61] distinguishes a form _P. nigroaculeata_, which is allowed by Mr. Lydekker. [Illustration] FIG. 54.--Australian Anteater. _Echidna aculeata._ x 1/6. {112}