466 REPORT OF NATIONAL MUSEUM, 1892. 



extinct toothed-birds of the genus Hesperornis y * and yet their nidifiea- 



tion is not as indicative of reptilian affinity as is that of some of the 

 higher groups. Of course it is not at all likely that Ave- shall ever 

 know what the eggs of any of the toothed birds looked like, or much less 

 what their breeding habits were, but it is fair to presume that it dif- 

 fered in important particulars from existing Pygopodes. I am of the 

 opinion, however, that all the early reptiles and reptile like birds laid 

 white eggs, of either an ellipsoidal or of a spheroidal form, and they 

 were not hatched by the parents. In number they may have been few 

 or many. 



Authors appear to be agreed that with respect to the Grebes they 

 build a nest of rushes and sedges, etc.. which to a greater or less extent 

 tloats upon the surface of the water in ponds and marshes among the 

 reedy growths there occurring. They differ, however, in their descrip- 

 tions of the eggs. Newton says their eggs have " a chalky white shell 

 almost equally pointed at each end;"-t Kidgway states "eggs 2 to 5, 

 dull white, bluish-white, or very pale bluish-green," while Cones 

 observes that " the eggs are more numerous thau in other pygopdous 

 birds, frequently numbering 6 to 8; elliptical, of a pale or whitish color, 

 unvariegated; commonly covered with chalky substance.f Dr. Sharpe, 

 in his Classification of Birds, says the eggs are white,§.but does not 

 mention the number laid by members of this group. Both in form and 

 color, then, Grebes' eggs remind us of reptiles', which is not the case in 

 either particular with the Divers. Here we tind according to Coues that 

 the Colymbidce "lay two or three dark-colored spotted eggs in a rude nest 

 of rushes by the water's edge" (loc. tit., p. 789), while Ridgway declares 

 the eggs to be but two, " elongate-ovate, deep brown or olive, latter 

 sparsely speckled or spotted with dark brown and blackish" {Inc. c/Y .,p. 7). 

 Sharpe says nothing about their being spotted, but that they are two 

 in number and of a "dark olive-brown" (loc. tit., p. 7). The eggs of these 

 birds are probably spotted and the fact is an important one, as it is not 

 only a point of difference between their eggs and those of the Grebes, 

 but in that particular they differ from the eggs of any known reptile. 

 They are the first eggs that have markings on them that we meet with 

 among the lower groups of our birds. The difference in form is equally 

 important, as it is likewise the first departure from the reptilian ellip- 

 soidal or spheroidal form of egg, it being in the Divers larger at one end 

 than it is at the other. 



The Tubinaees is another group wherein we find the birds laying, as 

 a rule, an ovate or subovate egg that may be spotted or pure white. 



*Shufeldt, R. V\\, Concerning the taxonomy of the North American Pygopodes, 

 based upon their osteology. Jour, of Anat. and Phys.. vol. XXVI, Loud., 1892. p. 199. 



tArt. "Grebe," Encycl. Brit.. 9th ed., Vol. XI, p. SO. 



,*l>i(lg\vay, Robert: A Manual of North American Birds, 18S7. p. t. For the 

 American Eared Grebe this author gives " eggs lour to eight" (p. ti). 



(ones. E. Key to North American Birds, ISSl. rev. ed.. p. 793. 



§Loc. cit., p. 71. 



