MACKIE — TUE AERONAUTS OF THE SOLENHOFEN A OK. 
5 
ostrich are thus reduced to nine in the adult. In the retention of 
the separate vertebrae of the tail, the Archseopteryx presents an ex- 
ample of the persistence of embryonic or more generalized characters, 
and affords a demonstration of the great truth, often obscured of late 
years, that there exists a certain representation of the career of any 
single animal in the various stages through which the life system of 
the world has passed. 
If there be any who yet entertain a doubt of the ornithic character 
of the specimen, and are misled by the occurrence of Archseopteryx 
in the Solenhofen slate, the very metropolis of Pterodactyles,- to 
suspect any reptilian affinities for it, we hope that they will compare 
the hind foot of the Archseopteryx with that of any bird, and with 
that of the longtailed Pterodactyle (Bamphorhynchus) from the 
same Solenhofen beds, in the Britisli Museum. In the birds we see 
the foot compact, stout, with an opposable hinder unguiculate digit, 
capable of prehension or of active support. In the reptile the homo- 
DlSTRIBUTION OF BiRDS. 
Gralla- 
Cursores. Rasores. llnsessoreslScansores.! Volitores.l Raptores. ^jgy^ggg^' 
Strata. 
Recent. 
Pliocene. 
Miocene. 
Eocene. 
Cretaceous 
Greensand 
Wealden. 
Oolite. 
Lias? 
Trias? 
Permian. 
Carboni- 
ferous. 
