30 S MURAL HlSrOIiY OF BIRDS. 



not difficult, witl) sucli material, to imagine, or rather to conclude, which were the lead- 

 ing j)eculiarilies in the lialiit of that strange water-bird inhabiting the great — now 

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

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

 h. fulh- 

 '-y/tf^/jeror;!!'* was a typical aquatic bird, and in habits was doubtless very similar 

 to the loon, although, fligiit being imi)os8ible, its life was probably psissed entirely upon 

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

 land at that time was the succession of low islands which marked the ]>osition 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 irreatest abundance and variety of fishes, and these doubtless constituted the 

 main food of the present species. Jltuperoriiis, as we have seen, was an ailniirable 

 diver, while the long neck, with its capabilities of rajiid fiexure, and the long, slender 

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

 ca))ture and retention of the must agile fish. As the lower jaws were united in front 

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

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



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

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

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

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

 gigantic li/ard, and with a large, broail, and flattened tail like a beaver. And extremely 

 para«loxical as is its external appearance, so is also its internal structure. 



Compared with Ichtliyornis, Ilesperoniis, on the whole, is the more specialized 

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

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

 develoj)eil ; thus, for instance, the teeth implanted in grooves, and not in sej)arate 

 sockets, as well its the long tail, — charactere 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 relationshi]) ; that is to say, lli;it the latter birds have sprung from :in ances- 

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

 IleKperctruis. 



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

 western Kansas, the Z,egtonii.i cra.'<sipeii is |iretty well est:d)lished to be near Ifespcr- 

 ornis. A nejirly complete skeleton was found in 1876 by .'\Ir. G. O. Cooper. This bird 

 is considerably larger than Ilcsperornis, and is remarkable for a ])rotuberance on the 

 inner side of the metatarsus, Mhich may have served as a sup]iort for a sort of 

 rudimentary spur. Many other remains of cretaceous birds, j)articularly from the 

 upi)cr deposits, liave been found and described in this country, but they are mostly too 

 fragmentary to allow more thim a guess .as to their relationships, anil, as hardly more 

 than a few bones are preserved of Jinptornis, Laoniis, (inioifavits, etc., it will 

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

 the so-calleil Knaliornis, have been found in the cretaceous deposits, and to these the 

 above remark is eipuilly a})plicable. 



Leoxii.vrd Stejxegee. 



