MONOTREMES. 333 



mallard (Anas boschas) and grey lag-goose (Anser cinereus) both 

 appear to be represented in the later deposits. Among the cave 

 deposits of France have been discovered the remains of the snowy- 

 owl (Nyctea Scandiaca) and willow-grouse (Lagopus albus), north- 

 ern forms which appear to have followed the southward migration 

 of the reindeer, and of a large extinct species of crane (Grus primi- 

 genia). Two or more species of swan have been found in the os- 

 siferous cavern of Zebbug, in the island of Malta, one of which, 

 Cygnus Falconeri, an extinct form, exceeded by about one-third 

 the dimensions of the common C. olor. 



Of the group of sub-fossil birds, or those whose remains belong 

 to a comparatively very recent period, are the giant struthious 

 birds of New Zealand, known as "moas" (Dinornis and Mionornis, 

 with some seven or more species), and the palapteryxes (Palapteryx 

 and Euryapteryx) ; the ^Epyornis maximus of Madagascar; and the 

 Australian Dromaeornis australis, the precursor of the modern emu. 

 A giant goose (Cnemiornis), associated with which are the remains 

 of several remarkable ralline forms (Aptornis and Notornis the 

 latter surviving up to our own period), and a number of other 

 birds, also occur in the newer deposits of New Zealand. In this 

 connection may be mentioned, although not strictly falling under 

 the category of fossils or sub-fossils, the recently exterminated 

 didine birds of the Mascarene Islands the dodo (Didus ineptus) 

 of Mauritius, and the solitaire (Pezophaps solitarius) of Rodriguez ; 

 the crested parrot of Mauritius (Lophopsittacus Mauritianus), and 

 the Aphanapteryx, an abnormal ralline species, from the same isl- 

 ands. 



MAMMALIA. 



Mo.'iotremata. This, the most limited, order of terrestrial 

 Mammalia, forming the sub-class Ornithodelphia of most natural- 

 ists, comprises two families, the Ornithorhynchidae, or duck-bills, 

 and Echidnidre, or Australian hedgehogs, the former of which is 

 restricted to the continent of Australia and Tasmania, and the lat- 

 ter to the same region with the addition of New Guinea. The 

 duck-bills are represented by a single species, the platypus or water- 

 mole of the colonists (Ornithorhynchus paradoxus or anatinus). 

 No fossil remains referable to this genus have as yet been dis- 

 covered. 



The Echidnidae comprise two recent genera : Echidna, with 



