The Echidna feeds like anteaters, by thrusting its tongue into an ant-hill, and waiting until it is covered with indignant and marauding ants, which are then swallowed. But this animal also devours worms and insects, which are extracted from their hiding-places by the tongue. It is mainly nocturnal, and prefers the seclusion of the densest scrubs of the bush, or rocky spots where it is free from intrusion. Dr. Semon did not find that the spur of this animal was used at all in self-defence; but he thinks that possibly the weapon may be used, in the breeding season only, in the combats of the males for the females, when perhaps, as has been shown to be the case in Ornithorhynchus, the gland attached to it produces a poisonous secretion.
The egg, as it appears, is transferred to the pouch by the mouth of the mother; the shell is broken by the emerging young one, which has an egg-breaking tubercle on its snout for this purpose; the mother removes the shell. When the young has attained a certain size, the mother removes it from the pouch, but takes it in from time to time to suckle it. When on her nightly rambles the young one is left in a burrow dug for the purpose. Dr. Semon was able, from his own observations, to substantiate this act of intelligence on the part of the Echidna. It is well known that the temperature of the Monotremes is less than that of higher mammals; in addition to this fact Dr. Semon found that the range of variation of temperature in the Echidna was as much as 13 degrees or more. It is thus intermediate between the "poikilothermal" reptiles and the "homoeothermal" mammals.
Fam. 2. Ornithorhynchidae.—There is no need to attempt to define this family, since it contains but one genus Ornithorhynchus, with but one species, O. anatinus. The general aspect of the animal is well known. It is covered with dense fur of a blackish brown colour; the limbs are short and five-toed, the toes being webbed. The tail is longish and broad, being flattened from above downwards. The webbing on the anterior toes considerably outdistances the tips of the claws, as in the Seals. But this is not the case with the hind-feet. The "beak," which is broad and flat, and does actually suggest that of a duck, is not covered with horn, as is often stated, but with a fine, soft, sensitive, naked skin, which abounds in sense-organs of a tactile nature. As to characters derived from the skeleton, Ornithorhynchus has seven-
