ME. J. EVANS ON THE AECHJIOPTEEYX. 417 



To those who have carefully examined the fossil, it may seem 

 superfluous to attempt to prove that these remains are really 

 organic ; but as I understand that some doubts have been expressed 

 upon this point, I would call attention to the following facts — 



1st. That the presence of a layer of calcareous spar of exactly the 

 same character as that which distinguishes the bones upon the slab 

 is evident around the bilobed projection on the principal slab, and 

 the mould hi the counterpart in which they were formed is a con- 

 tinuation of the same sparry layer. 



2ndly. That assuming this sparry layer to represent the former 

 existence of bone, as to my mind it undoubtedly does, there is no bone 

 which presents an analogous bilobed cavity with the exception of the 

 skull ; and 



Srdly. That the position of the remains refers them to the 

 Archseopteryx, while the ornithic character of the cast of the brain 

 cavity is in perfect accordance with the other portions of the skele!;on 

 of this curious creature. 



I therefore regard the evidence on which rests the attribution of 

 this part of the fossil to the head of the Archseopteryx as sufficiently 

 conclusive to justify som-e further speculation upon the subject. 

 I would, however, rather leave this to others better versed in anatomy, 

 and will only venture upon a single suggestion with regard to the 

 position of the brain in relation to the beak. 



Although from the nature of the matrix in which the skull was 

 imbedded, there has probably been some compression and distortion 

 of its form, yet these appear to have been but slight and not sufficient 

 to aifect in any material degree the shape of the interior cavity, of a 

 portion of which we have here a cast in indurated mud. For the 

 sake of comparison I have made plaster casts of the brain-cavities of 

 a number of birds belonging to different orders ; and though I find a 

 considerable range in the proportion of the brain-cavity to the other 

 parts of the skull, and also in the character and extent of the inter- 

 cerebral ridge, yet the general resemblance of the anterior portion of 

 the brain of all the birds which I have examined to that of the 

 Archseopteryx is most distinct. The casts of the interior of the 

 forepart of the skulls of the Jay and the Woodcock {Garrulus glan- 

 darius and Scolopax rusticola) more particularly exemplify this 

 resemblance. "We may from this and from the presence of feathers 

 (as was so well pointed out by Professor Owen), infer that the 

 Archseopteryx was provided with a beak more or less analogous in 

 character with that of other birds. 



N.H.R.— 1865. 2 F 



