FAUNA OF THE POST-PLIOCENE. 359 



The Invertebrate animals of the Post-Pliocene deposits re- 

 quire no further mention all the known forms, except a few 

 of the shells in the lowest beds of the formation, being iden- 

 tical with species now in existence upon the globe. The only 

 point of importance in this connection has been previously 

 noticed namely, that in the true Glacial deposits themselves 

 a considerable number of the shells belong to northern or 

 Arctic types. 



As regards the Vertebrate animals of the period, no extinct 

 forms of Fishes, Amphibians, or Reptiles are known to occur, 

 but we meet with both extinct Birds and extinct Mammals. 

 The remains of the former are of great interest, as indicating 

 the existence during Post-Pliocene times, at widely remote 

 points of the southern hemisphere, of various wingless, and for 

 the most part gigantic, Birds. All the great wingless Birds of 

 the order Cursores which are known as existing at the pres- 

 ent day upon the globe, are restricted to regions which are 

 either wholly or in great part south of the equator. Thus the 

 true Ostriches are African ; the Rheas are South American ; 

 the Emeus are Australian ; the Cassowaries are confined to 

 Northern Australia, Papua, and the Indian Archipelago; the 

 species of Apteryx are natives of New Zealand; and the 

 Dodo and Solitaire (wingless, though probably not true Cur- 

 sores), both of which have been exterminated within histor- 

 ical times, were inhabitants of the islands of Mauritius and 

 Rodriguez, in the Indian Ocean. In view of these facts, it 

 is noteworthy that, so far as known, all the Cursorial Birds 

 of the Post-Pliocene period should have been confined to the 

 same hemisphere as that inhabited by the living representatives 

 of the order. It is still further interesting to notice that the 

 extinct forms in question are only found in geographical prov- 

 inces which are now, or have been within historical times, inhab- 

 ited by similar types. The greater number of the remains of 

 these have been discovered in New Zealand, where there now 

 live several species of the curious wingless genus Apteryx; and 

 they have been referred by Professor Owen to several generic 

 groups, of which Dinornis is the most important (fig 257). 

 Fourteen species of Dinornis have been described by the Dis- 

 tinguished palaeontologist just mentioned, all of them being 

 large wingless birds of the type of the existing Ostrich, having 

 enormous powerful hind-limbs adapted for running, but with 

 the wings wholly rudimentary, and the breast-bone devoid of 

 the keel or ridge which characterizes this bone in all birds 



