94 Proceedings of the Royal Physical Society. 
superior connections of the vomer in the horse are peculiar, 
inasmuch as the inferior surface of the leaflets of the ethmoid, 
instead of lying in contact, as is usual, with the ethmo-vomerine 
lamina for a considerable extent, is completely floored in by 
the upper part of the palate bone, which is expanded for that 
purpose. Even in the horse, however, a slender lamina, im- 
mediately in front of the palate bone, and in contact with its 
nasal foramen, passes downwards and inwards on each side 
from the framework of the ethmoidal turbinations to the mar- 
gin of the vomer ; but the vomer and it are not anchylosed 
until other sutures also have begun to be obliterated. 
The vomer in the rodentia is remarkable in having very 
little tendency to come in contact with the superior maxilla- 
ries. As far as I have observed, it is always continuous with 
the lateral masses of the ethmoid. 
In the skull of the rahhit there is only one great anterior 
palatine foramen ; for, although the mesial processes of the 
intermaxillaries project well backwards, the palate plates of 
the superior maxillaries do not come far enough forwards to 
meet them. The vomer does not at all approach the superior 
maxillaries; its posterior margin terminates inferiorly in a 
thickened angle, which articulates with the intermaxillaries in 
such a manner as to make their inferior aspect continuous with 
the posterior margin of the vomer. In front of this, the laminae 
bounding its groove are prolonged on the upper surface of the 
intermaxillaries, as we have seen in other animals (fig. 4). 
In the porcupine and squirrel the vomer is not in contact 
with the superior maxillary bones ; in the rat and the beaver 
it is. 
In the quadrumana the mesial process of the intermaxil- 
laries is so slightly developed that the anterior extremity of 
the vomer frequently falls short of it by a slight interval. In 
monkeys the vomer and orbital plates of the ethmoid are con- 
tinuous ; but in the skull of a young Chimpanzee in the Uni- 
versity Museum, the arch of bone which unites them is sepa- 
rated at one extremity from the ethmoid by a suture, and at 
the other only touches the vomer. This piece of bone has all 
the essential characters of the sphenoidal spongy bones of the 
human subject. 
