300 report — 1846. 



e. g. in Simia. In the rhinoceros it supports a dermal spine or horn. The 

 pleurapophysis (20) or proximal element of the haemal arch of the nasal ver- 

 tebra has its real character and import almost concealed by the excessive 

 development of the second element of the arch (21), which resumes in mam- 

 mals all those extensive collateral connections which it presented in the cro- 

 codile ; and to which are sometimes added attachments to the expanded spine 

 of the frontal vertebra, as well as to that of its own segment. The pleurapo- 

 physis however, besides its normal attachment to its centrum, 13, sends up a 

 process to the orbit, in order to effect a junction with its neurapophysis which 

 sometimes appears there, as the ' os planum' of anthropotomy. The hcemal 

 spine (22) is developed in two moieties, which never coalesce together, al- 

 though, in the higher apes, and at a very early period in man, each half 

 coalesces with the hasmapophysis, and repeats the simple character of the 

 corresponding elements (rami) of the succeeding (mandibular) arch. 



The appendicular element (24) which diverges from the pleurapophysis 

 (20), contributes to fix and strengthen the palato-maxillary arch by attaching 

 it to the descending process of the parietal centrum (5) ; with which, in most 

 mammals, it ultimately coalesces. The other elements of the diverging mem- 

 ber of the arch correspond in number and in the point of their divergence 

 with those in birds, chelonians and crocodiles. They are two in number, suc- 

 ceeding each other, and both become the seat of that expansive development 

 which is followed by the multiplication of their points of connection ; thus 

 the proximal piece ('malar' 20) articulates in the hog not only with the 

 hasmapophysis (21) from which it diverges, but likewise with the mucc-dermal 

 bone, 73. The distal piece of the appendage (squamosal, 27) expands as it 

 diverges, and fixes the naso-haemal arch not only to the frontal pleurapo- 

 physis (2s), but also to the frontal, parietal and occipital neurapophyses and 

 spines : it also affords, in the hog, as in other mammals, an articular surface 

 to the frontal hagmapophysis (29). 



The development of an osseous centre in the cartilage of the snout of 

 the hog, and the homologous ' prenasal ' ossicle in certain fishes, the carp, 

 e. g., might be regarded as rudiments of terminal abortive segments more 

 anterior than the nasal vertebra. The multiplied points of ossification in the 

 vomer have been, also, deemed indications of that bone being, like the vome- 

 rine coccygeal bone in birds, a coalescence of several vertebral bodies. Of 

 course, a, priori, the segments in the cranial region of the endoskeleton 

 might as reasonably be expected to vary in number in different species, as 

 the segments in the thoracic or sacral regions. I have not, however, been 

 able to determine clear and satisfactory representatives of more than four 

 vertebrae in the skull of any animal ; and the special ossifications in the nasal 

 cartilages appear to me to belong to the same category of osseous parts, as 

 the palpebral bones in certain crocodiles and the otosteals. 



Man. — Arriving, finally, in the ascensive survey and comparison of the 

 archetypal relations of the bones of the vertebrate skull,atMan,thehighest and 

 most modified of all organic forms, in which the dominion of the controlling 

 and specially adapting force over the lower tendency to type and vegetative 

 repetition is manifested in the strongest characters, we, nevertheless, find the 

 vertebrate pattern so obviously retained, and the mammalian modification of it, 

 as illustrated in the preceding paragraph and diagram, so closely adhered to, 

 as to call for a brief notice only of those developments of the common 

 elements which impress upon the human skull its characteristic form and 

 proportions. 



The neural arch of the occipital vertebra differs from that of the hog by 

 a much greater development of the neural spine (fig. 25, 3) and a much less 



