VERTEBRATE PALEONTOLOGY IN 1913 627 



only the outer half of each being capable of being bent back- 

 wards in the direction of the body. They could not walk like 

 quadrupeds, and if they waddled like ducks, it must have been 

 with extended wings : this being so, it seems doubtful if they 

 could swim, or even touch and rise from the surface of the 

 water, let alone dive. On land, they may perhaps have pushed 

 themselves along on their bellies like penguins and divers, and 

 they may have started their flights by throwing themselves 

 from cliffs. It is further shown that the upper wing-bone, or 

 humerus, is articulated to the shoulder-girdle by a hinge-joint, 

 working only in an up-and-down direction, instead of, as in 

 birds, by a ball-and-socket, permitting movement in any 

 direction. In consequence of this, combined with the fact that 

 the flexure of the complex elbow-joint permitted of a somewhat 

 wider range of movement, it is inferred that the flight of 

 pterodactyles was chiefly or solely of the soaring type of that 

 of the albatross, this being probably connected with the weak- 

 ness of the flying-muscles, as indicated by the low elevation of 

 the crest of the breast-bone. This weakness of the flapping 

 muscles is not, however, to be taken as an indication of poor 

 flying power ; but rather that every ounce of such power 

 was used. 



One difficulty, to which the authors make no allusion, on 

 the theory that these reptiles could not dip into the water 

 when in flight, arises in connection with their feeding habits. 

 Unless they subsisted on insects, they must have obtained their 

 food in the water. That they did not live on insect-food is 

 rendered practically certain by the loss of teeth in the later 

 forms, which implies a change of diet, as, for example, from 

 hard-scaled fishes to soft belemnites or other cephalopods. It 

 may be added that the authors are disinclined to accept the 

 hypothesis, referred to in a previous article of this series, of 

 increased atmospheric pressure in earlier epochs as an aid to 

 the flight of pterodactyles. 



Among other publications relating to fossil reptiles which 

 have appeared during the year, a foremost place may be assigned 

 to a series of three articles by Dr. H. von Huene, published as 

 pt. 1 of ser. 2, vol. xiii. of the Geol. und Pal. Abhandlungen. 

 They respectively relate to (1) the history of the Archosauria, 

 (2) certain pterodactyle skulls, and (3) the structure and 

 affinities of the Saurischia. In the first it is held that the 



