On the Vomer in Man and the Mammalia. 95 



The vomer and sphenoidal spongy bones in man. — Having 

 found the vomer and lateral masses of the ethmoid so univer- 

 sally connected, we naturally inquire how they are related in 

 man. They are not in contact. Their only connection is 

 that the expanded portion of the vomer which grasps the 

 rostrum lies beneath the sphenoidal spongy bones, and that 

 these articulate with the lateral masses of the ethmoid. Now, 

 seeing that the sphenoidal spongy bones are recognised as 

 ossifications distinct from the sphenoid, I think we have 

 already sufficient evidence to prove that they represent the 

 ethmo-vomerine laminae, by aid of what we have noticed in 

 the Chimpanzee's skull ; for it is impossible to doubt either 

 that the distinct bone which lies between the orbital plates of 

 the ethmoid and the vomer in that skull corresponds to the 

 ethmo-vomerine lamina of other monkeys ; or, on the other 

 hand, that it corresponds to the sphenoidal spongy bone in 

 man. But the correspondence becomes much more distinct 

 when we study the early condition of the sphenoidal spongy 

 bones. The most interesting condition of these bones is when, 

 in the skulls of young children, they can be got completely 

 ossified and not yet destroyed by amalgamation with the 

 neighbouring bones. In this state the sphenoidal spongy 

 bone is somewhat of the shape of a hollow pyramid with the 

 apex directed backwards, its inner aspect parallel to its fellow, 

 and its cavity (the first form of the sphenoidal sinus) opening 

 at its base into the nasal cavity in front (fig. 2). This pyramid 

 is constructed by the union of at least three distinct pieces of 

 bone. Firstly, there is an orbital piece, forming a portion of 

 the wall of the orbit between the ethmoid and sphenoid, an 

 element, I believe, in the formation of the orbital wall not 

 hitherto observed. It articulates with the orbital process of 

 the palate bone, and, together with the inferior piece, com- 

 pletes the nasal foramen of the palate-bone, namely, the fora- 

 men called spheno-palatine, but which we have seen to be 

 invariably ethmo-palatine in other animals. The superior 

 piece bounds the sphenoidal sinus above and on the inside, 

 and ultimately becomes incorporated with the sphenoid bone. 

 The inferior piece is the largest of the three ; it forms the 

 floor of the sphenoidal sinus, and the under half of its opening 



