Revieivs — W, Barnes — On Archceopteryx. ■ 421-' 



The eye is surrounded above and behind by bony fragments, in the' 

 centre of which lies a suture (not clearly definable). It is present in 

 all adult birds, uniting the frontal and parietal bones which inclose 

 the brain. At the union of these two bones, the skull is broken away, 

 showing that the brain-cavity is filled with calc-spar. Although the 

 bones behind the eye are much injured and displaced, they may still 

 be made out ; the temporal fossa is not present, but the brain was 

 incased in a compact bony covering, such as is characteristic of the 

 skulls of living birds. The greater part of the brain lay behind the 

 eye, in which the head of Arclmopteryx agrees well with living birds. 

 The frontal bone seems to continue forward from above the orbit as 

 far as the middle of the antorbital vacuity ; at least no suture is 

 visible. The antorbital vacuity expands upwards posteriorly, 

 narrows in the middle, and expands somewhat towards the front. ^ 

 Its posterior margin forms the front border of the orbit. This I 

 term the lachrymal bone; it unites with the maxillary bone. It is 

 probable that the upper border of this opening is divided from the 

 nasal, but, as with the frontal bone, no suture is observable. The 

 lower border must have been formed by the maxillary, and in part 

 also by the intermaxillary ; but as the bone is here much broken, no 

 very accurate border can be given. Its form is that of a right angle 

 triangle, with rounded points. The length is 9 mm., the height 8 

 mm. Within the antorbital vacuity lies an irregular four-sided piece 

 of bone ; in my former notice of the skull I thought this was due to 

 compression ; now that it is more fully developed, I am enabled to say 

 more decidedly that this piece of bone is the palatine process of the 

 maxilla. There appear to be two pieces of bone resting upon one 

 another; the lower perhaps is a part of the vomer or one of the 

 median septa. But a more accurate determination is prevented by 

 the state of preservation of the specimen. Immediately in front of 

 the antorbital vacuity lies the third opening, the nasal foramen. It 

 has a lengthened elliptical form somewhat pointed at the ends. It 

 lies lengthwise, nearly parallel to the upper edge of the skull, and 

 is 8 mm. long, its greatest breadth being 4 mm. The nasal foramen 

 is bordered above by scarcely 1 mm. width of bone, the forward 

 continuation of the nasal bones or else the ascending ridge of the 

 intermaxillary. Its border passes under and forward from the inter- 

 maxillary. There are still the following parts of the skull to 

 describe. There is a long bone scarcely 1 mm. wide joining the 

 lower end of the bone I call the lachi-ymal ; it extends in a straight 

 line towards the back of the skull, its upper part was covered with, 

 matrix ; its length and form suggest it to be the quadratojugal ; but 



1 The antorbital vacuity in most recent birds is confluent with the anterior nasal 

 foramen (e.g. Alca, Aptomis, hinornis), not distinctly separated as in Archmopleryx. 

 JJidus shows a bar between the vacuities, but in Pezophaps it is wanting. In Apteryx 

 the anterior nostril is most remote from the ortorbital vacuity. (See Owen's Extinct 

 Wingless Birds, pi. i. fig. 1, pi. Ixxxiii. fig. l,pl. Ixxv. fig. 1, pi. viii.) Odontopterpx 

 (Q. J. G. S. vol. xxix. pi. xvi. fig. 2m) shows an extensive tract of bone between the 

 nostril {n) and the antorbital vacuity (73, fig. 8), the corresponding dividing plate 

 between the antorbital and nasal openings in Archaopteryx is narrow when compared 

 with Odontopteryx, the antorbital vacuity being very large in the former. 



