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ON THE EXTINCT BIEDS OF THE CHATHAM ISLANDS. 



I'AHT I.— THE OSTEOi.UGV OF DIAPHURAPTERYX IIAWKINSI. 



By C. W. ANDREWS, F.G.«. 



(Plat.- III.) 



I Is .March IS'JH Or. II. (>. Forbes announced, in a telegram to Naliwc* that he had 

 received from the Cliatham Islands, a grouii lying about oOO miles east of New 

 Zealand, a skull of a species of Aphanupteryx, for which he proposed the name 

 Aijhanapteryx hawkinsi. He subsequently f paid a personal visit to the islands, 

 and succeeded in obtaining a large collection of bird remains, including the more 

 important parts of the skeleton of Aph. haivkinsi, as well as of several other extinct 

 forms. These he has since named and in part described in various journals. In 

 a paper in the Ibis (189o, p. 254), following the advice of Prof. Newton, he referred 

 Aph. Iiaivkinsi to a new genus, Diapliorapteryx; but afterwards (torn. vit. p. 450), 

 having himself examined the specimens on which Milne-Kdwards founded Aphanup- 

 teryx broecki, he reverted to his original opinion and withdrew his new name. 



During last summer, through the kindness of the Hon. Walter Kothschild, I 

 liad an opportunity of examining an immense collection of bird remains from the 

 Chatham Islands, consisting of many thousands of bones, mostly in good condition, 

 and including numerous skulls and other portions of the skeleton of Dlaphwapteryx. 

 In addition to the isolated bones, there are one or two more or less complete skeletons 

 which are of great value for purposes of determination. The great bulk of the 

 collection consists of remains of recent seabirds, such as Albatro.sses, Cormorants, 

 and Penguins; but, in addition to Diaphorapteryx,, there are many other extinct 

 forms, including some large species of Fidica, (?) Cabalus dieffenhachii, Pcdaeocwax 

 moriorum, and there are also a few seal bones, some human metapodials and 

 jihalanges, remains of rats and mice and of fish, but I have not found any reptilian 

 bones whatever. 



I'^xamination of so large a mass of material has rendered it possible, not only to 

 obtain nearly complete skeletons of several of the extinct species, but also to form a 

 fairly accurate idea of the degree of individual \ariation occurring in some of them. 

 In the present paper I jiropose to consider the skeleton of Diaphm'apjteryx hau'Jdnsi 

 only, the other species being reserved for a future communication. 



OSTKOLOtiV (»F DIAPIlOliM'TRRYX IIAWKIX.SI Fuuhk.s. 



The skull. — Ciiiii)iarisou of I he skull with IIiosh of ( Icyilroiniis and t'ubalns shows 

 a( once its great similarity to them. The most noticeable differences are — (1) the 

 greater proportionate length of the beak; (2) the larger and more clearly defined 

 temporal fos.sae : (IS) the more si I'ongly develo])ed paroc('i]iital, maiiimillary, postorbital, 

 and other liony jirocesses. The last two characters ju-e clearlv correlated with the 

 increased size and weight of the skull and mandible, which render necessary larger 



» V.il. XLV. lKfl2, |j. I HI. t yaliirc. Vol. .\LV. l.S!t2, p. 5S0. 



