Revieios — W. Barnes — On Archceopteryx. 423 



The lower jaw retains its articulation with the skull by means of 

 the quadrate bone. It is a long and narrow bone ; the lower border 

 is curved very gradually upwards ; it is broader behind than in front. 



Breadth, at the articulation 4-5 mm. 



,, below the lachrymal 3-5 „ 



,, ,, last tooth in upper jaw 2-75 „ 



4th „ „ 2-0 „ 



Behind the articulation with the quadrate bone, there is a post- 

 articular process which is 4 mm. long and 2 mm. high ; the entire 

 length from the posterior extremity to the symphysis is 35 mm. 

 That with such decided dentition as that of the maxillary and inter- 

 maxillary, the lower jaw could not be toothless, both Marsh and I 

 foresaw. The jaw, however, is attached to the specimen as if the 

 beak was closed, so that little is to be seen of the dentition. To my 

 great joy I have succeeded in finding the point of a tooth directed 

 upwards between the 3rd and 4th intermaxillary teeth; also under 

 the 3rd tooth of the upper jaw, on the edge of the lower jaw, stands 

 the broken remains of a tooth, and lastly a tooth may be perceived 

 under the antorbital vacuity behind the teeth of the upper jaw. So 

 much may be generally stated of the teeth of the lower jaw. That 

 there were teeth in front, and also in the middle of the border of the 

 jaw, may be assumed with great certainty, that in fact the lower jaw 

 had teeth corresponding to those in the upper. It is not easy to say 

 if there was a vacuity in the middle of the lower mandible. In 

 one place in the back part, the matrix is seen ; but the edges of this 

 opening are so irregular and broken that one inclines more to the 

 opinion that this opening is simply a hole broken through the sur- 

 face of the jaw. Unfortunately, the counterpart, which might have 

 proved this, is missing. Lastly, there are two little needle-like bones 

 belonging to the head, which from their form and length can be none 

 other than the hyoid bones. One lies below the posterior border of 

 the under jaw, and projects backwards beyond it where it is broken 

 off, whilst in front it is hidden beneath the lower jaw, so that its 

 full length cannot be ascertained ; the piece seen is 14 mm. long. 

 The other bone lies higher up above the lower jaw, and behind the 

 quadrate bone ; it is nearly parallel to and like that already noticed ; 

 it is 3 mm. long ; it is most probably a part of the hyoid bone of the 

 left side. This bone lies in front of a fragment of another bone 

 that I am disposed to call the post-articularis of the left side of the 

 lower jaw. 



The foregoing description of the skull and lower jaw of Archao- 

 pteryx leaves some parts still hypothetical, owing to the state of 

 its preservation. This is particularly the case as regards the back 

 part of the skull, and also the separate elements of which it is com- 

 posed. Still a more or less exact picture is given, which on the 

 whole bears many analogies with the skulls of living birds. 



That it is a true bird's head is apparent, although the presence 

 of teeth seems anomalous. But the researches of Prof. Marsh had 

 already proved the presence of numerous Birds with teeth in the 

 Cretaceous epoch. The Archceopteryx seems, however, to be more 



