140 Transactions. — Zoology. 



bones, are by themselves sufficient evidence to show that the 

 remote ancestors of the EatitjE could fly. Palaeontology con- 

 firms this opinion, because the oldest known bird — Archceo- 

 ptcryx, of the Jurassic period — had well-developed wings. 



With the exception of some peculiarities in the base of the 

 skull, all the other characters w4iich unite the Eatitae into one 

 group, including their great size, are merely adaptations to a 

 terrestrial life, and are of little value as evidence of affinity. 

 Even the characters of the skull are not confined to the 

 Eatitae, but are also found in the tinamous and Ojnsthocomus, 

 which are carinate birds. 



The living Eatitae form four well-defined families — 



1. Strut] iionidcB, containing the two-toed ostrich of 

 Africa. 



2. Bheidce, containing the rhea of South America. 



3. Gasuaridai, including the emu and cassowary of Aus- 

 tralia and Melanesia. 



4. AjpterygidcB, containing the kiwi of New Zealand. 



The moas — Dinornithidae — come between the Casuaridae 

 and the Apterygidae, connecting them together. Contem- 

 poraneous with the moas were Dromornis and an extinct 

 species of emu in Australia, a large extinct species of rhea 

 in Brazil, and ^'pT/ornis in Madagascar. The last of these 

 was a struthious bird, but it is doubtful where it should 

 be placed. Certainly it was not closely allied to the moas, 

 although it resembled some of them in its gigantic size, and 

 in having a hind-toe. In the early part of the Pliocene 

 period an ostrich lived in northern India, as also did 

 another with three toes, perhaps allied to the rhea ; and 

 here we come to the earliest certain traces of struthious birds 

 outside oi New Zealand. In the Lower Eocene, Dasornis, 

 Mcgalornis, and Macroornis, of Europe, "'' as well as Dia- 

 tryma, of Mexico, are thought by some to belong to the 

 Eatitas. The fragment of the skull of Dasornis is said by 

 Professor Owen to resemble the skulls of BJiea and Struthio 

 more than that of Dinornis. The fragmentary shaft of the 

 tibia of Megalornis is compared to that of the emu by Professor 

 Seeley.f Professor Cope thinks that Diatryma was allied to 

 the rhea, while Mr. Lydekker thinks it may be identical with 

 Gastornis. Great size may go either with aquatic or with 

 terrestrial habits, and there is as yet no conclusive proof that 

 any of these birds belong to the Eatitae ; and certainly there 



• Gastornis is said both by A. Milne-Edwarcls and E. T. Newton to 

 be related to the Anatidse (Trans. Zool. Soc, vol. xii., p. 143) ; but 

 Mr. Lydekker places it doubtfully in the Ratitre [Knoivledge , 1891, and 

 Nicholson's "Palaeontology," vol. ii.). 



t Quar. Jour. Geol. Soc, vol. xxx., p. 708. 



