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In reference to the peculiarities presented by the vomer and eth- 

 moid in the human subject, the author endeavours to show that their 

 relations are really in agreement with those which he has described 

 as typical among mammalia. He found the key to the interpretation 

 of the arrangement seen in the adult, by examining the condition of 

 the bones in very early life, especially the sphenoidal spongy bones. 

 The last-mentioned bones are described in young subjects as consist- 

 ing of hollow pyramids enclosing the sphenoidal sinuses, but origin- 

 ally quite unconnected with the sphenoid. They articulate on the 

 one hand, edge to edge with the alse of the vomer, and on the other 

 with the ethmoid and the palatals, and by their contact with the 

 orbital and sphenoidal processes of the latter, complete on either side 

 the so-called sphenopalatine foramen, and correspond altogether to 

 the ethmovomerine laminae and part of the ethmoid in other mammals. 



The human vomer can be seen in its perfection as a separate bone, 

 and with all its connexions fully developed, in early life only ; and 

 an explanation is offered of the peculiarities of the human vomer and 

 ethmoid, by showing that they are consequences of the great curvature 

 of the cranial arch, the small development of the organ of smell, and 

 the prolongation of the face downwards for the sake of voice, instead 

 of forwards as in other animals, for the sake of prehension. 



The connexions of the vomer, ethmoid, and intermaxillaries in the 

 various families of mammals are next examined in detail, and various 

 differences of form, &c. peculiar to genera and orders are noticed. 

 Attention is particularly drawn to the circumstance that in the camels 

 and other ruminant families the intermaxillaries are prolonged for- 

 wards beyond the points of junction of their lateral plates and mesial 

 palatine processes, so as to embrace more or less completely the 

 anterior extremity of the septal cartilage of the nose, which between 

 these prolongations dips into the palate ; and that, similarly, the 

 intermaxillaries meet above the septal cartilage in the Dugong,Manati, 

 and Tapir, in which they have no mesial palatine processes : to these 

 forms importance is afterwards attached in comparing the intermax- 

 illaries of mammals with those cf birds, reptiles, and fishes. 



The author argues that the vomer, lateral masses of the ethmoid, 

 and palate-bones are members of one segment ; that the central plate 

 of the ethmoid is the centrum of the segment behind ; and that the 

 mesial palatine processes of the intermaxillaries play the part of cen- 



