THE SKELETON OF THE VERTEBRATE HEAD. 1*75 



jecting from the sides of the cranium, like the auditory 

 capsules, they occupy the space of the corresponding cranial 

 segment. The incomplete cartilaginous rings of the nasal 

 tube, viewed in their relations to the cranium and conjoined 

 olfactory capsules, are in the position of a superadded series 

 of neural arches, similar to the neural portions of the rhinal 

 and vomerine mammalian sclerotomes, destitute, however, of 

 centrums, but supported below by the peculiarly-developed 

 palatine and maxillary elements which have passed forward 

 beneath them. The entire arrangement presents the general 

 characters, or is developed on the plan of the nasal fossae of 

 the reptile, bird, and mammal, with the additional peculiarity 

 of an increase in the number of constituent segments, similar 

 to that which apparently exists in the proboscidian mammals. 



POST-STOMAL CEPHALIC SCLEROTOMES. Their Central and 

 Neural Elements. As the discrimination of the constituent 

 central and neural elements of the three post-stomal segments 

 of the skull demands a constant reference from the one seg- 

 ment to the other, I shall examine them together. Of these 

 three segments the post-sphenoidal, the temporal, and the 

 occipital the second has not hitherto been recognised except 

 by Carus, whose system includes a temporal intervertebra. 



My attention was directed to the temporal segment of the 

 cranium by the remarkable indications of it presented by the 

 human skull. The human occipital bone, in addition to that 

 upper angular portion of its squamous plate, which presents 

 the relations of the interparietal, exhibits all the character- 

 istics of a vertebral centrum, in combination with neura- and 

 meta-neurapophyses. The inferior articular processes of this 

 cranial segment are largely developed, in relation to the atlas. 

 But it has not been hitherto noted, that the so-called jugular 

 processes are in fact its upper or anterior pair of articular 

 processes ; and that, consequently, the jugular processes on 

 the posterior margins of the petrosal portions of the temporals 



