14 R. W. Shufeldt 



11.5 centimeters, and was, at some time or other, broken into about 

 twenty fragments, fairly good repair having been made through the 

 use of glue and plaster-of-paris. 



So far as I am aware, this is the only material in existence repre- 

 senting this extinct bird, and Professor Marsh's description of it is 

 given in sufBcient detail for all practical purposes of comparison. 

 He believed the bird to be ''distinct from Hesperornis, and of smaller 

 size, but evidently belonging to the same general group of gigantic 

 swimming birds." This may or may not have been the case, and he 

 may have been influenced in his opinion by the fact that the specimen 

 was found "associated with marine fossils of Fox Hills types, and 

 certainly from a much higher horizon than that in which Hesperornis 

 occurs" (loc. cit., p. 81). 



Professor Marsh further believed that the distal portion of a bird's 

 tibio-tarsus, including a fair part of the shaft, "is a most character- 

 istic part of the skeleton," of which statement it may be said that it 

 is not nearly as much so as is the distal portion of the tarso-meta- 

 tarsus, or the proximal moiety of a humerus. We may make grave 

 errors in relying too much on the characters presented on the part of 

 the distal moiety of the tibio-tarsus, when we have in our possession 

 for comparison only this portion of the skeleton. If we meet with 

 marked differences in it, as compared with the corresponding ones in 

 the bone of the species with which it is being compared, then we 

 may be quite certain that the balance of the skeleton may be very 

 different indeed, and may, in fact, not belong to the same group of 

 birds at all. 



This specimen evidently belonged to an "adult bird," as Marsh 

 states, for the epiphyses are most firmly united to the distal end of 

 the shaft. He further observes that this "tibia as a whole was very 

 long and slender, with the shaft hollow throughout," in which surmise 

 he was probably correct, although the statements are based purely 

 upon indications. He found, too, that "In its general features, the 

 specimen resembles most nearly the corresponding part in Hesperor- 

 nis. The general proportions of the two are similar. The cavity in 

 the shaft of each is equally extensive, and is bounded by smooth, 

 well-defined walls. The ridge for the fibula is equally developed, 

 indicating that this bone was proportionately of the same length in 

 both, and probably of the same form. 



"The differences between the present fossil and the corresponding 

 part in Hesperornis are, however, strongly marked. In the latter, 

 the distal end of the tibia is curved inward, and the smaller inner 



