the Head in Ornithosaurs. 35 



saurian skull, I should have adopted it. And still it is a 

 point that requires additional evidence to pronounce upon 

 decisively. Should the bird-like interpretation (to which, 

 from the forward position of the orbits &c., I least incline) 

 eventually prove tenable, it would take away the evidence for 

 the anomalous cerebral characters which have already been 

 dwelt upon, and bring both brain and brain-case into a more 

 absolute conformity with birds than I have felt justified in 

 assuming. Still no such bone has ever been found in Ptero- 

 dactyles, and at present there is no proof that it existed. 



The only other point in which Cambridge specimens appear 

 to differ from those of Germany is the squamous character of 

 the quadrato-jugal bone*. 



I come to the last word about the skull, not because our 

 knowledge is completed, but because there are no more bones. 

 New specimens in time will fill in the lacunai which have 

 been indicated, and modify our doubtful determinations ; but 

 so much of the skull is now known that no specimens can 

 unsettle or invalidate its avian affinities. And if a contro- 

 versy nearly as old as modern zoology thus ends, it is because 

 the more philosophical and severe science of om* time has 

 taught us to find an animal's place in nature by study of the 

 common plan on which it is built, rather than in the old mor- 

 phological way, which would predicate an entire organism from 

 the form of a quadrate bone or a caudal vertebra. And the result 

 gives strength to an old law of Cuvier's, which hitherto has 

 never failed — that the pneumatic skeleton is always asso- 

 ciated with avian organization. So that henceforth, just as 

 we infer from the double-fanged tooth the lungs and heart, 

 and brain and reproduction, of a mammal for the animal to 

 which it belonged, so now we may infer for the animal which 

 had limb-bones with pneumatic foramina the organization and 

 systematic grade of a bird. Side by side with birds, the 

 Ornithosauria are a monument of the faithfulness of Nature 

 to her laws, and a new pledge to the student that she never 

 will betray the heart that trusts her. 



* A new genus appears to be constituted by some (three) portions of jaws 

 from the Cambridge Greensand. Unfortunately, the extremity is noi 

 preserved. They have the ordinaiy dagger-shaped snout, but appear to 

 be entirely destitute of teeth. I provisionally name the genus Ornitho- 

 stoma. 



Another unnamed generic type is typified by Pterodactyhis longicoUmn, 

 P. rhamphastinus, and the two species included under the name of F. Kochi. 

 In this genus the middle hole of the skull is entirely wanting. For it I 

 suggest the name Diopecephalus. 



3* 



