30 NATURAL HISTORY OF BIRDS. 



not difficult, with such material, to imagine, or rather to conclude, which were the lead- 

 ing peculiarities in the habit of that strange water-bird inhabiting the great now 

 fossilized sea of the far west, many, many thousand years ago. Not being able to 

 improve on Professor Marsh's account, we take great pleasure in introducing it here 

 in full : - 



" Hesperornis was a typical aquatic bird, and in habits was doubtless very similar 

 to the loon, although, flight being impossible, its life was probably passed entirely upon 

 the water, except when visiting the shore for the purpose of breeding. The nearest 

 land at that time was the succession of low islands which marked the position of the 

 present Rocky Mountains. In the shallow tropical sea, extending from this land five 

 hundred miles or more to the eastward, and to unknown limits north and south, there 

 was the greatest abundance and variety of fishes, and these doubtless constituted the 

 main food of the present species. JSesperornis, as we have seen, was an admirable 

 diver, while the long neck, with its capabilities of rapid flexure, and the long, slender 

 jaws armed with sharp, recurved teeth, formed together a perfect instrument for the 

 capture and retention of the most agile fish. As the lower jaws were united in front 

 only by cartilage, as in serpents, and had on each side a joint which admitted of some 

 motion, the power of swallowing was doubtless equal to almost any emergency." 



If, allowing our imagination, within logical bounds, to cover the bones of the 

 skeleton, figured above, with flesh, skin, and feathers, what a strange creature rises 

 before our eyes! A bird indeed, but a kind of swimming, loon-like, raptorial ostrich, 

 without fore limbs, with the gape armed with formidable rows of strong teeth like a 

 gigantic lizard, and with a large, broad, and flattened tail like a beaver. And extremely 

 paradoxical as is its external appearance, so is also its internal structure. 



Compared with Ichthyornis, Hesperornis, on the whole, is the more specialized 

 form as is indicated by its saddle-shaped vertebrae, its atrophied keel of the breastbone, 

 and its rudimentary fore limbs. But several other features, on the other hand, are less 

 developed; thus, for instance, the teeth implanted in grooves, and not in separate 

 sockets, as well as the long tail, characters retained from their common ancestor, 

 which may be looked for in some older deposit than the cretaceous formation. 



Most of the characters which we have mentioned as Struthionine or ostrich-like, 

 are really only reptile-like, having the same signification among the Struthiones, though 

 some features for example, the arrangement of the shoulder girdle seem to indicate 

 a nearer relationship ; that is to say, that the latter birds have sprung from an ances- 

 tral stock not very distant, allied to that strangest of all strange birds, the ancient 

 Jfesperornis. 



The systematic position of another cretaceous bird from the Pteranodon beds of 

 western Kansas, the Lestornis cmssipes is pretty Avell established to be near Jfesper- 

 ornis. A nearly complete skeleton was found in 1876 by Mr. G. O. Cooper. This bird 

 is considerably larger than Hesperornis, and is remarkable for a protuberance on the 

 inner side of the metatarsus, which may have served as a support for a sort of 

 rudimentary spur. Many other remains of cretaceous birds, particularly from the 

 upper deposits, have been found and described in this country, but they are mostly too 

 fragmentary to allow more than a guess as to their relationships, and, as hardly more 

 than a few bones are preserved of J3aptornis, Laornis, Graculavus, etc., it will 

 be sufficient to mention their names. In Europe numerous remains, among which is 

 the so-called Enaliornis, have been found in the cretaceous deposits, and to these the 

 above remark is equally applicable. 



LEONHAKD STEJXEGER. 



