658 



THE GREATEST FLYING CREATURE. 



reduced, and the extreme of reduction is found in the frigate bird, 

 which, with a spread of wing of 6 feet 4- inches, has a muscular area 

 of only 3.50 square inches." 



There is another point in the anatomy of Omithostoma besides 

 length of pinion that lends strength to the supposition that it sailed, 

 and this is found in the structure of the fore limb. It was pointed out 

 by Mr. Huffaker that in spite of the deficiency of muscle shown by 

 soaring birds the support of the wing was very strongly built; thus the 

 frigate bird with its small breastbone has the bones of the shoulder 

 joint firmly united with one another and with the breastbone. In the 

 albatross strength is gained by shortening and widening the bone to 

 which the wing is directty fastened and giving it a broad base for 

 attachment to the breastbone. In the great pterodactyls strength 

 was obtained by bracing the shoulder blade against the backbone, in the 



manner shown in the diagram; thus the 

 body, so to speak, was slung from the 

 wings. In addition, three sections of 

 the backbone were united in one piece 

 in order to give a firm point of attach- 

 ment, the whole arrangement curiously 

 suggesting the fore leg of a turtle. 



In spite of its great extent of wing. 

 Omithostoma was not a heavy animal, 

 possibly not so heavy as the trumpeter 

 swan, for the body was small and the 

 bones reached the extreme of lightness, 

 being far lighter than in any bird. This 

 may be appreciated by ([noting Professor Williston's remark that the 

 bones were almost papery in their character, one of the finger bones 

 26 inches long and 2 inches in diameter being no thicker than a cylin- 

 der of blotting paper. The same authority, basing his estimate on tnis 

 extreme lightness of structure and the small size of the body, places 

 the weight of one of these pterodactyls at only 25 pounds, and with 

 this weight and its great spread of wings the creature must have flown 

 as lightly as a butterfly. Even if we increase the estimated weight by 

 20 per cent, we have a creature weighing but 30 pounds, so that tin 1 

 body was even more an appendage to the wings than in the frigate 

 bird, and seems to have been just heavy enough to counterbalance the 

 weight of head and neck and insure equilibrium. 



How tin' wing of Ovntthostoma is sii| 

 ported. 



"This is stated with some hesitancy, as no sternum of a large albatross is available, 

 and it may be that, all things considered, the albatross has the least amount of wing 

 muscle. The ratio of wing muscle to wing is smaller in the turkey buzzard than in 

 the frigate bird, being, respectively, 1:125 and 1 : 114, this owing to the much broader 

 wing of the buzzard. On the other hand, the great humming bird {Patagona gigas) 

 lias a ratio of muscle to wing area of 1 : I'M, ami a small species a ratio of hut 1:1 1.39. 



