( 2U0 ) 



ON THE EXTINCT BIRDS OF THE CHATHA:\r ISLANDS. 



Part II.— THK OSTEOLOGY OF PALAEOLIMXAS CUATHAMENSIS 

 AND NESOLIMNAS (Gkx. Now) DIEFFEXDA rillL 



By C. W. ANDREWS, F.G.S. 



(Plates IX. and X.) 



Q1IXCE tlip publication of the first part of this paper (antea, pp. 73-84), dealing 

 ^ with the osteology of Diaphorapteryx hmvkinsi, there has appeared a memoir 

 by Professor A. Milne-Edwards,* containing descriptions both of that bird 'and also of 

 I'ahteolimnas {Fuiica) chathamensis Forbes, a large e.xtinct coot. As the title 

 implies, questions of geographical distribution are largely dealt with, but the structure 

 and affinities of the two species just named are al.so considered in some detail, and 

 numerous figures of various portions of their skeletons are given. Unfortunately the 

 material at the author's command was far from perfect, and in one instance a serious 

 error has resulted, the pelvis figured (PL XI., fig. 7, and PI. XII., figs. 1, 2) as that 

 of Diaphorapteryx being quite unlike it, but, judging from the figures, belonging to 

 some Anserine bird. The actual pelvis o{ Diaphorapteryx is shown in figs. 1, 2, and .3 

 of PI. IX. of the present pa})er. 



On the question of the geographical distribution of these flightless birds Professor 

 Milne-Edwards arrives at different conclusions from those expressed in Part I. lie 

 apparently regards such forms as capable of supplying evidence as to the former distri- 

 bution of land and water as valuable as that derivable from mammals and batrachians, 

 and considers that the presence of similar types of such birds on two land-areas 

 remote from one another implies a former land-connection between them. From this 

 point of view, however, it seems that a sharp distinction should be drawn between 

 birds which, except for the reduction of their wings and sternum, are true Cannatcie, 

 and are easily referable to their systematic position in that group, such as Didus and 

 C'lieraiornis, and those flightless forms included in the Ratitae, which, leaving 

 entirely out of account their wing-reduction, present numerous primitive characters 

 which render it, at least, highly probable that they reached thr>ir present degenerate con- 

 dition a very long while ago. Only the latter of these two divisions appears to be of 

 value in questions of ancient geography, since, as alreadv pointed out, the presence 

 of members of the former class on i.-^hands is capable of explanation without the aid of 

 land-connections. Thus, if any close affinity is proved to exist between the Aepym~)vl- 

 thidae, Caauariidae, and Dinornithidae, it might be regarded as strong evidence that 

 the lands they now inhabit were once united; while, on the other hand, in the case 

 of the existence of such similar forms as Aphawvpteryx and Diaphorapteryx, in 

 Mauritius and the Chatham Islands respectively, we are probably dealing with 

 parallel modifications of recent date. 



* " Sur Ics Eesscmblanoes qui existent entre la Kaune elcs lies llascaroigne.i et celle de certaincs lies 

 dc rOcean Pacifiquc Australe," ^JWiofcs des Sciences NahireUes (Zoology), Ser. VIII., Tom. II. (18!l(i), p. 117, 

 ri9. XI.— XV. 



