232 EARLY STUDIES IN COMPARATIVE ANATOMY 



tlie interlocking, which he compares to that of a latch 

 and its hasp. All these features are illustrated by an 

 excellent model, better than those usually given in recent 

 text-books. Perrault dwells too on the advantages of 

 the curvature of the vane, on the power of inclining the 

 wing-quills, and on the facility with which ruffled barbs 

 can be adjusted by stroking; in the ostrich, as he 

 shows, the barbs are unconnected, and the quills cannot 

 be variously inclined. He points out the action of the 

 head, neck and legs in the flight of large birds, and 

 dispels the fallacy that birds fly by virtue of their low 

 specific gravity. 



Poupart (1669) figures late stages of developing 

 feathers, showing among other things the formative 

 papilla and the pile of dry cones (German Seele), into 

 which it ultimately shrinks. 



M^ry (1689) describes the respiratory movements of 

 a bird. He remarks that in a live goose the thorax 

 dilates during inspiration, the sternum receding from 

 the backbone, and the ribs from one another. The air- 

 sacs, which had been described and figured by Perrault, 

 become distended as the thorax expands. 



The most interesting bird-paper of this age is Mery's 

 description of the woodpecker's tongue (1709). Borelli 

 and Perrault had already treated the same subject, but 

 M^ry aspired to give a more exact description than 

 either of his predecessors, and his account has become 

 celebrated as a masterpiece in the delineation and inter- 

 pretation of natural contrivances. The adaptation which 

 he explains makes it possible for the woodpecker to 

 protrude at pleasure a stiff and slender tongue, long 

 enough to probe the burrows of wood-boring insects. 

 When the mouth is opened, nothing is seen of the 

 tongue-apparatus except a pointed, horny scale, which 



