Jan. 1887.] 



a:n^d oologist. 



9 



and previous ideas of ray own. Where are the 

 scientists of the future V I doubt not many of 

 tliem are among^ the readeas of the Oknithol- 

 OGIST AND Oo LOCUST, and if I give even one of 

 tlieni "a peg to hang an idea upon," I shall feel 

 sure I have done well. 



Several years ago 1 had an indistinct idea that 

 birds might be descended from two types of an- 

 cestors, and that Grebes and Terns were very 

 ancient forms surviving with less change from 

 their earlier families than many other types. 

 Among Batrachians we tind two types, — the 

 Frogs and the Newts — which develope quite 

 difterently and it seems to me as if the Grebes 

 and Terns were respectively analogous to them. 

 My belief in their antiquity was based upon the 

 fact that the waters of the glol)e were early 

 fitted for their existence, and that up to the 

 present time there had been fewer changes in 

 their favorite habitat than in that of such l)irds 

 as frequent woodland resorts. Between these 

 two and by a similar course of reasoning, I 

 placed on the one hand the l)each birds and on 

 the other the Kails, Herons and their allies. 



The Grebes have strong hind limits. The 

 Frog's hind legs are the tirst to develop. The 

 Terns are remarkably strong of wing. The 

 fore-leg of the Ne\\ t are the first to appear. In 

 Professor Marsh's work the huge Grebe retains 

 its tail. I picture to myself the big diver strug- 

 gling with its prej% held fast in its strongly 

 toothed jaws and able to regain the surface of 

 the water with comparative ease by means of 

 its powerful rudder. 



On the other hand, the Terns being early 

 fitted for flight would have less use for this 

 appendage. Their aerial gyrations were better 

 directed by a wide feathered caudal adjunct. 

 Hence their superfluous verte))r;e were lost at a 

 very early date, and their place supplied by the 

 delicate forked tails which now survive. 



Possibly a reminesence, — the word is ex- 

 pressive rathei' than correct in this connection, 

 — of teeth still exists and accounts for the 

 lengthening of the bill of the Royal Tern. 1 

 have often noticed this myself and Cones men- 

 tions it in his Birds of the Northwest. 



The transitions from one to the other of the 

 three adaptations of the vertebra;, — hollowed, 

 jointed or faced, is very easy and no doubt re- 

 quired but a comparatively short period to be 

 thoroughly accomplished. Professor Marsh 

 points out a close similarity between the Royal 

 Tern and one of his ancient forms. In the neck 

 is the last vestige apparently, of the vertel»ra 

 peculiar to the ancestral type. The Grebes 

 found early the need of a long and flexible 



neck. In the huge extinct species it was also 

 no doubt strong and muscular, as figured in 

 the article by Dr. Shufeldelt in the Century 

 magazine. But the Terns capturing their prej' 

 from above the watery element by a well aimed 

 dash, had no need of such an extent of material 

 in the neck, and hence the ancestral type of 

 vertebra remained less modirted in them. 



The above considerations seem to me to pre- 

 clude any strictly consecutive arrangement of 

 birds into classes. Many havt; doubtless met 

 with the same difficulty that I encountered long 

 ago when ceitain families, do all I could, would 

 seem to arrange themselves in parallel lines. 



If the consiilerations which I am discussing 

 are sufficiently tenal)le to form the basis for a 

 good theory, the parallel or gradual diverge- 

 ment and consecjuent system of classification, 

 will be the more correct one. 



Eggs of the Broad-winged Hawk. 



RY .T. P. N. 



The size of tlie eggs of this species, (Buteo 

 peiDist/h-anlrns) has often been incorrectly given 

 by writers. It is almost always stated to be 

 larger than a series of eggs of this hawk would 

 seem to indicate — thus leading to the suspicion 

 that the eggs described were not really those of 

 Buteo pemisylvanicus, but ])robably often those 

 of Buteo lineatus. 



Audubon does not give measurements of the 

 eggs of this species, but says that they "are 

 four or five, of a dull grayish-white, blotched 

 with dark brown." Experience seems to i)rove 

 that tliey are but rarely four and never five. 



Dr. Brewer, in his Xorth American Oalof/y, 

 thought that three eggs were the usual imm- 

 ber for this bird, and gave the size of three 

 single eggs in his cabhiet, collected in Penn- 

 sylvania, Vermont and New Jersey, as follows : 

 2 1-10x1 9-l(i; 1 1.5-l(>xl S-Ki; and 1 14-l()xl 8-10 

 inches. He figured three eggs in Plate I. of 

 his work, collected in New Jersey, Pennsylva- 

 nia and Florida. Measuring these illustrations 

 with calipers gives this result: Figure S, (from 

 New Jersey,) l.i)9xl.55; Figure*.), (from Peiui- 

 sylvania,) 2.00x1.58; Figure 10, (from Florida), 

 2.08x1.0:^ inclies. 



Samuels (in his Ornitholofjij and Oology of 

 New Em/land) relates that he found a nest of 

 this ( species on May 20, 1804, in West Rox- 

 bury, Mass., that contained four eggs. He 

 gives their measurements as varying from 2.00 

 xl.70 to 2.15x1.72 inches. Their color was "a 



