THE AMERICAN MUSEUM JOURNAL 







Characinidre and Exocoetidae, have met 

 with any measiu'e of success — and 

 many people aver that neither of these 

 really fly. 



Also it is worthy of note that none 

 of the flying or sailing animals use the 

 hind legs actively; bats, flying squirrels, 

 even flying fish, simply use the hind 

 limbs as adjuncts to flight, holding them 

 motionless to spreafl a membrane or 



Tetrapteryx stage, when the "pelvic wing" of birds 

 was at its height of development and use 



to the point at all, especially since a 

 large number of observers say that the 

 flying fish does not fly, although in this 

 we believe them mistaken. 



Those who favor the jumping down 

 theory, as opposed to the jumping up, 

 can on the contrary show almost every 

 stage in the progress from flightlessness 

 to flight, beginning with lizards that, 

 like the iguana, jump boldly from their 

 abiding places on the branches, to the 

 flying lemur that can sail — or para- 

 chute — for a hundred yards or more. 

 Even snakes that drop from trees ha^•e 

 developed — or there has been de^•el- 

 oped in them — an ability to hollow in 

 the under side of the body, which affords 

 some slight resistance to the air. Not 

 only this, but true flight has also been 

 developed in three classes of vertebrates : 

 reptiles, birds and mammals, in the order 

 of their appearance in time; and if it 

 failed to develop in fishes and amphi- 

 bians, it may well be ascribed to the fact 

 that neither of these groups were tree 

 climbers and when tree frogs <lid appear 

 they were too highly specialized to make 

 a success of flight. 



As to fishes, they were handicapped by 

 the structure of their fore limbs, and al- 

 though representatives of several orders 

 have essa;yed to fly, only two groups, the 



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Archa!opteryx stage, when the wings were increasing 

 in power and the "pelvic wing" was going into disuse 



form a kitelike support for the hinder 

 end of the body. The hind legs are used 

 to jump with, not to run with, save in 

 sea birds that, like the albatross in a 

 calm, may run a quarter of a mile before 

 getting headway enough to launch him- 

 self into the air. But where would a 

 lizard get a good straight away level 

 stretch? 



The new evidence that Mr. Beebe 

 brings forward to show that flight began 

 by sailing, consists of a series of sprout- 

 ing quills, found in newly hatched birds 

 of several species, running from the 

 outer, upper part of the leg just below 

 the knee, nearly to the base of the tail. 

 These ciuills are placed just where, if 

 developed, they woidd form a sort of 

 winglet on either side, which combined 

 with the tail would aft'ord excellent sup- 

 port for the hind part of the ])0(ly during 



