212 A MANUAL OF THE BIRDS OF AUSTRALIA. 



Generally the Grebes have been placed distant from the Rails, but there can 

 be little doubt that this is their correct place. The palate of the skull is 

 schizognathous and the nasals holorhinal, and there are no basipterygoid processes. 

 It has been written by an osteologist that it would be difficult to find differences in 

 the skulls of the Grebes and Rails. The cervical vertebrae are twenty-one in number, 

 the sternum is one notched and there is no anterior spine, and the procoracoid is 

 absent. There is only one carotid and the digestive system does not appear to 

 have been particularly studied, but may be similar to the Ralline style. The leg 

 muscle formula is BX , which is instructive. The oil gland is tufted, the aftershaft 

 present and the wing aquincubital. The pterylosis has not been comparatively 

 determined, and the swimming downy nestling is of a peculiar striped coloration. 

 While fossils are on record as suggested relations of this group, as this has continually 

 been confused with the phylogenetically distinct group of Divers (= Colymbiformes, 

 a suborder of theLari or Limicolse), it is difficult to consider such at present. Thus 

 the Hesperornithes from the Cretaceous of North America have been regarded as 

 showing ancestral features of both Grebes and Divers, but such conclusions do not 

 seem to have been based on sound premises, and most of the resemblances noted 

 are simply due to similar environmental stresses. 



FAMILY PODICIPID^. 



The limits are those of the order, and some workers are diffident in accepting 

 many genera, as the ordinal form is omnipresent. However, both osteologists and 

 anatomists have recorded, according to their views, important items for separation, 

 so that distinct genera must be accepted. Thus the syrinx in Podiceps and Pclio- 

 oephalus is of different form, while the skull shows numerous differences also. It 

 must be noted that the swimming habits of the Grebes have developed a strong tibial 

 crest ; this is the most marked feature for the association of this group with the 

 Divers, but it is so purely an adaptive feature that it is difficult to understand why 

 much stress was laid upon it with regard to phylogenetic relationship. 



Genus PODICEPS. 



Podiceps Latham, Gen. Synops. Suppl., Vol. I., p. 294, (pref. May 1st) 1787. Type (by 



subsequent designation, Gray, p. 76, 1840) : Colyrtibus cristatus Linne. 



Colymbus Illiger, Prodr. Mamm. et Av., p. 281, (pref. April) 1811. Type (by subsequent 



designation, Ogilvie-Grant, Cat. Birds Brit. HUB., Vol. XXVI., p. 502, 1898): Colymbtu 



cristatus Linne. 



Not Linne, Syst. Nat., 10th ed., p. 135, Jan. 1st, 1758. 



Lophaithyia Kaup, Skizz. Entwick.-Gesch. Nat. Syst., p. 72, (pref. April) 1829. Type (by 



monotypy) : C. cristatus Linne. 



Largest Grebes, with long straight bills, short rounded wings, rudimentary 

 tail and peculiar, flattened tarsi, and largely lobed toes with broad, flattened claws. 

 Bill long, straight, and pointed, sometimes slightly curved at the tip ; nostrils 

 pervious, and placed at the base of the upper mandible. Wings very short and 

 rounded, the feathers narrow and pointed, the first longest, the secondaries usually 

 as long as the primaries. Tail rudimentary, consisting of a tuft of downy feathers, 

 no rectrices being distinguishable. Tarsus shorter than the middle toe and claw, 

 compressed so as to form a ridge anteriorly and posteriorly, where it is serrated. 

 The toes are flattened and surrounded by large lobes of skin, only connected at the 

 base, not contracted at the joints. The claws are also flattened, forming part of 

 the lobe ; the fourth toe is the longest, the hallux is small and also provided, like 

 the others, with a lateral lobe. The anterior ridge is regularly scutellate, and the 



