OF THE VOMEE, ETHMOID, AJ^D INTEEMAXILLAET BONES. 
297 
from the vomer ; but on the left side their suture of connexion with the ethmoid has 
begun to disappear, and it scarcely comes into contact with the vomer. In the smallest 
skull, the sphenoidal spongy bones are perfectly free from the ethmoid on both sides, 
and also free from the vomer, though in contact with it ; but while that on the left side 
is perfectly free from the sphenoid, the right one is anchylosed with the anterior inferior 
margin of that bone. In the remaining skull, the sphenoidal spongy bones are separate 
from the orbital plates of the ethmoid, but are anchylosed with the sphenoid both in 
front of the foramen opticum and below, also with the vomer, and with a turbination of 
the ethmoid. In all three cases the sphenoidal spongy bones take part in the formation 
of the orbit, while the palatal has no orbital plate. 
The shape of the posterior extremity of the vomer aifords us a very distinctive differ- 
ence between the skulls of the Orang and Chimpanzee, which I believe has not hitherto 
been noticed. In the Orang it is expanded, flat, and with irregular edges. In the 
Chimpanzee it is thick, comparatively narrow, with straight edges, bifurcated, and fitted 
into a groove so as to leave a canal between it and the sphenoid. These characters are 
well marked even in the extremely young skull. In the Gorilla the posterior extremity 
of the vomer has expanded irregular edges as in the Orang, while it is bifurcated and a 
canal is left above it as in the Chimpanzee* (fig. 6). 
In the Bat^ the intermaxillaries are extremely small ; they do not come together in 
the middle line, and have no mesial-palatine processes ; they therefore have no connexion 
with the vomer. 
In the Carnimra, the vomer and ethmoid are quite typical in their arrangement. In 
the Cats, the Dogs, and the Bears, the mesial plate of the vomer reaches a short way 
back upon the palatals. In the new-born Kitten the sphenoid, vomer, and intermaxilla- 
ries are seen in a very instructive condition. The body of the presphenoid is not yet 
compressed into a septum, and the two projections from the wings of Ingeassias, which 
afterwards meet beneath so as to enclose the sinuses, are as yet but little processes ; the 
vomer passes forwards in a straight line from the front of the body of the presphenoid ; 
and beyond the vomer this line is continued by the intermaxillaries, while the surface 
for articulation of the vomer with the maxillaries is as yet a mere knob. This arrange- 
ment is calculated strongly to suggest the idea of a series of centra (fig. 7, D). 
* In the engraving of the base of the skull of a Chimpanzee in the Trans. Zool. Soc. vol. iii. pi. 60, 
illustrating Professor Owen’s paper, “ Osteological Contributions to the Natural History of the Chimpanzee,” 
the canal along the middle line of the sphenoid is represented as completed behind the vomer by junction 
of the roots of the pterygoid bones, or in other words, by the vaginal processes meeting together in the 
middle line. This completely conceals from view any parallel-bordered part of the vomer which may be sup- 
posed to rest between these and the body of the sphenoid. The skull represented is that of a male. The 
representation of the vomer of the GoriUa in pi. 63, illustrating the same paper, agrees with the description 
given above. My sketch was taken from a Gorilla’s skull in the Museum of the Jardin des Plantes, Paris. 
In the skull of a young male Chimpanzee in Dr. Allen Thomson’s possession the pterygoids have already 
almost met in the middle line, as represented in Professor Owen’s drawing, while the vomer is compressed 
between them. Most probably this is a sexual characteristic. 
MDCCCLXII. 2 S 
