Jurassic Birds and their Allies. 
338 
some care the three known specimens of Archwopteryx. I have 
also studied in the Continental Museums various fossil reptiles, 
including Compsognathus, which promised to throw light on 
the early forms of birds. 
During my investigation of Archeopteryx, I observed several 
characters of importance not previously determined, and I have 
thought it might be appropriate to present fei here. The 
more important of these characters are as follows :-— 
The presence of eae teeth, in position, in ‘a skull. 
Vertebree biconcav 
A well-ossified, rob stern 
Three digits only i in ie manus, , all with claws. 
Pelvic bones separat 
The distal end of fibula i in front of tibia. 
Metatarsals separate, or imperfectly united. 
Toe ete ere 
These characters, taken in connection with the free sense 
pe and ve tail, gts described, show clearly that w 
ave in Arche opterycc most remarkable ‘for rm, which, if a bird, 
as I believe, is carteinky the most reptilian of birds. 
now we examine — varions characters in detail, their 
importance will be a 
he teeth actually in  pouteini in the skull appear to be in 
the fapnoaags es as the “y are below or in front of the nasal 
apertur orm of the teeth, both crown and root, is very 
similar ee me Dak of Hesperornis. The fact that some teeth 
are scattered about near the jaw would suggest that they were 
implanted in a groove. No teeth are known from the lower 
jaw, but they were probably present. 
The presacral vertebre are all, or nearly all, biconcave, 
eeatnblitig those of Jchthyornis in general form, but without 
the large lateral foramina. There appear to be twenty-one 
presacral vertebrae, and the same, or nearly the same, 1 number 
of caudals. The sacral vertebra are fewer in number than in 
any ‘nova bird, those united together not exceeding five, and 
probably less. 
The scapular arch strongly resembles that of modern birds. 
The articulation of the scapula and coracoid, and the latter 
with the sternum is nei oz and the furculum is dis- 
tinctly avian. The sternum is a single bead plate, well 
ossified. It Rear supported a art) but this is not expose 
in the known specim 
In the wing itself the main interest centers in the manus and 
its free metacarpals. In form and position these three bones 
are just what may be seen in some young birds of sige 
