Fossil Birds in the Marsh Collection of Yale University 15 



condyle is especially prominent below. In the present specimen, 

 the outer condyle is the lower, and the inner one is nearly on a Une 

 with the inner margin of the shaft." (See PL III.) 



On the twenty-fourth of March, 1914, the United States National 

 Museum loaned me the cast of the left tibio-tarsus of Ilesperornis 

 regalis, a privilege I am most grateful for, as I am to Mr. J. W. Gidley 

 and to Mr. C. W. Gilmore of that institution for placing the specimen 

 in my possession for the purposes of photography. This I accom- 

 plished the following day, Plate IV being a reproduction of the 

 photographs made from my negatives. They present the lower 

 half of the shaft on the three principal views, corresponding with 

 those I present of Coriornis alius on Plate III. 



The cast of this tibio-tarsus is of the same bone — with its imper- 

 fections restored — which Marsh figures in five \dews in the Odon- 

 torniihes (PL XIV, Figs. 1, 2, 2a, 3 and ?>a), it being from the left 

 pelvic limb. 



Marsh's figures are of natural size, and have been so drawn that 

 the compressed parts in the original have been altered so as to restore 

 their probable normal bulk and proportions, which anyone will ap- 

 preciate by comparing them with my figures, which are, as I have 

 stated, reproductions of photographs made direct from the specimen, 

 they having been reduced rather more than one-fifteenth. 



As examples of the aforesaid alterations, I may say that in Professor 

 Marsh's ^gz«T5 (1 and 3) the transverse diameter of the distal end of 

 the bone just above the condyles measures 3.4 centimeters, whereas, 

 on the actual specimen, the same diameter measures but 3 centi- 

 meters. Posteriorly, the intercondylar valley or space in Marsh's 

 Figure 3 measures transversely 2.1 centimeters, while in the specimen 

 the same diameter is but 1.6 centimeters. 



The caliber of the distal moiety of the shaft presents the same 

 form, and all its diameters are the same in Marsh's figures of this bone 

 as they are in the specimen; they also agree for the longest antero- 

 posterior diameter of the external condyle. 



We are not concerned here with the proximal moiety of this bone, 

 for the reason that we have not that part for Coniornis altiis. 



I have carefully compared the characters of the distal end of the 

 tibio-tarsus of the latter bird with the corresponding ones in the 

 tibio-tarsus of Hesperornis regalis, and I do not find them to be so 

 much at variance as Marsh made them out to be; indeed, they are 

 no greater than would be presented on the part of two good species of 

 Hesperornis, in so far as this part of the tibio-tarsus is concerned. In 



