3^ 



THE AMERICAN NATURALIST. 



[Vol. XXXVII. 



The three bones composing one-half of the pelvis were appar- 

 ently distinct, quite as much so as among the young of modern 

 birds. Of these pelvic bones the ilium is best seen, and is said 

 to be characteristically avian. Apart from a few transitional 

 characters denoting the origin of the form from reptilian stock, 

 the skeleton of the pectoral and pelvic limbs are almost entirely 

 ornithic. Whether the avian-like humerus was pneumatic has 

 not as yet been definitely decided. This is due to the fact that 

 the pneumatic fossa is still concealed in the matrix. A low 

 pectoral crest was developed, a feature we would naturally 

 look for, as doubtless these birds could fly well. Three well- 

 developed digits composed the skeleton of either hand ; the first, 

 or pollex, having two phalanges, index three, and medius four. 

 All of the distal or ungual phalanges supported claws. The 

 carpus, according to Pycraft, "probably agreed with that of 

 modern birds ; except that the distal mass of fused bones 

 remained distinct throughout life, and that digit III was pro- 

 vided with a separate carpal bone." Every anatomist who has 

 examined the pelvic limbs of these fossil forms declares that the 

 skeleton of the pelvic limb is almost entirely avian in character, 

 Professor Gadow having noticed that the metatarsal to the 

 hallux digit was short and free, being directed backwards. 

 Others have observed, as Professor Dames and Dr. Hurst, the 

 reduction of the distal extremity of the fibula, but whether the 

 bone stands in front of the tibia, as in Iguanodon, and stated by 

 Dr. Stejneger, seems to be doubtful. The metatarsals were 

 elongated as in existing birds, and apparently firmly ankylosed 

 together, though their original separateness is easily made out 

 by the presence of the sutural lines between their shafts. 

 Including the hallux there were four toes, as in the higher bird 

 groups of this day, and their ungual phalanges were all armed 

 with a horny claw. Archceopteryx possessed a femur departing 

 in general structure and appearance but very little from what 

 characterizes that bone in any medium-sized corvine type of the 

 present time, and so requires no special description. There 

 seemed to be, however, considerable curvature to its shaft In 

 addition to the authorities I have already named as havino-' con- 

 tributed to the knowledge of these Jurassic birds, may be "added 



