the Head in OrnitJiosaurs. 21 



ment on their kindred ; for there is no snout among living 

 animals like the Pterodaetyles'. Even the extinct animals 

 which are already known manifest no signs of kindred. If 

 among the Teleosam-ia a like progressive enlargement of the 

 first three teeth and then a narrowing of the jaw is seen to 

 show again a character of many Omithocheiroid jaws, it is 

 but a solitary resemblance ; and the Teleosaur's snout, with 

 its terminal single nostril, is in no other way a counteii:)avt. 

 If Ichthyosauria as invariably have the nostril far back 

 from the end of the snout, it in no other way resembles Ptero- 

 dactyles' ; for the premaxillary bones are separate and dense in 

 tissue, and have no sockets, but only a simple groove for teeth. 

 If, in triangular dagger-shape and bone-texture, some of the 

 species recall birds, still birds have no teeth, even the imma- 

 ture parrots showing but evanescent enamelled specks ; while 

 other species end their jaws in a bulbous truncate way, which 

 among birds is never seen. And if we seek for a denticulate 

 jaw among lizards, we shall not find the bird-like elongation 

 of snout, or its Teleosaur-like widening or flattening of palate, 

 and not typically socketed teeth. Yet to birds (and lizards) it 

 approximates best, but in such obscm-e ways as to stand apart 

 with an individual isolation which would admit of its kindred 

 being reptiles, or mammals, or birds, without amazement to 

 the osteologist. It is not a nose that leads. 



Similarly, if only the back of the skull had been found, it would 

 have been more a matter of scientific taste than of scientific fact 

 to have said whether it showed stronger similitude to tooth- 

 less birds like the heron, or a toothless mammal like Myrmeco- 

 phaga or the foetal Orycteropus'^ . Therefore to one who would 

 consider these Cambridge exuviae in the old moi-phological 

 way, estimating the affinities bone by bone and adding them 

 together to get the total affinity, there is room for considerable 

 doubt and justifiable difference of opinion about the restoration 

 of the head and its resemblance to that of other animals. 



I have now an opportunity of lessening that doubt by the 

 discovery of the frontal bone. (PI. II. fig. 1.) 



The specimen is referred to an Ornithosaurian because it 

 possesses the peculiar thin, dense, and smooth bone charac- 

 teristic of the class, which has been found in no other fossils 

 of the Cambridge Greensand ; and it is identified as the frontal 

 bone because it resembles the bone so named in certain rep- 

 tiles, birds, and mammals, and is not like any other element 

 of the skeleton. The fossil is broken both in front and be- 



* The occipital condyles are not preserved with the adjacent bones in 

 Cambridge fossils, and the auditory region is filled with phosphate of 

 lime. 



