1018 MR. Av. P. pycEAri on the [Dec. 19, 



2. Contributions to the Osteology of Birds. 

 Part IV. Pygopodes. By W. P. Pycraft, A.L.S. 



[Eeceived September 11, 1899.] 

 (Plate LXXII.) 



i. Introductory Remarks, p. 1018. 



ii. The Skull of the Adult, p. 1019. 

 iii. The Skull of the Nestling, p. 1028. 

 iv. The Vertebral Column, p. 1033. 



V. The Ribs, p. 1034. 

 ■vri. The Sternum and Pectoral Girdle, 



p. 1035. consulted, p. 1044 



\ii. The Pelvic Girdle, p. 1036. I 



Contents. 



viii. The Pectoral Limb, p. 1037. 

 ix. The Pelvic Limb, p. 1037. 

 X. Summary, p. 1041. 

 xi. Key to the Osteology of the 



Pygopodes, p. 1042. 

 xii. List of Works referred to or 



i. Intboductory Eemarks. 



The following account of the Osteology of the Grebes and 

 Divers is offered as a supplement to the very valuable memoirs of 

 Brandt, Beddard, Milne-Edwards, Piirbringer, Gadovv, Garrod, 

 D'Arcy Thompson, and others, to which the present writer is 

 greatly indebted. Although, perhaps, few of the facts herein set 

 down are really new, it is hoped that the method of their presen- 

 tation may succeed in bringing to light points which have hitherto 

 escaped notice. As usual, this work is based upon a study of 

 the skeletons in the Natural History Museum. These are fairly 

 numerous, but some genera of Grebes yet remain on our lists of 

 desiderata. 1 am especially indebted to Mr. Beddard for the loan 

 of a skeleton of ^chmopTiorus, which is as yet unrepresented in 

 the Collection. 



We have no embryos either of Grebes or Divers ; hard-set eggs 

 of these would therefore be very acceptable. The only nestling- 

 skeletons of this suborder which we possess are two of Podidpes 

 cristatus, kindly furnished for the purposes of this paper by the 

 Hon. "Walter Eothschild, M.P. 



My description of the hemipterygoid of the Diver is based upon 

 two nearly full-grown skulls, one of which was kindly lent me by 

 Prof. G. *B. Howes, F.R.S. Nestlings of the Diver are badly 

 needed. We should be grateful for help in this direction from 

 members of this Society, some of whom doubtless could fill up for 

 us these gaps. 



Comparison is frequently made, throughout this paper, between 

 the Auks and Divers. This is in no sense to be taken as a 

 suggestion that these two forms are in any way related. The 

 points wherein the two resemble one another are many, but they 

 are to be i^egarded as instances of convergence, brought about by 

 similar habits of hfe. It is intended to make such comparisons a 

 special feature of this series of papers, in order that they may be 

 of real use to the working osteologist and palaeontologist, both of 

 whom are freq^uently called upon to decide to which of two forms 



