338 report— 1846, 



their differential and subordinate characters, and to voluntarily abdicate the 

 power of appreciating and expressing them. The terms ' secondary ' or 

 ' tertiary vertebrae ' cannot, therefore, be correctly applied to the parts or 

 appendages of that natural segment of the endoskeleton to the whole of 

 which segment the term 'vertebra' ought to be restricted. 



So likewise the term ' rib ' may be given to each moiety of the haemal arch 

 of a vertebra; although I would confine it to the pleurapophyses when they 

 present that long and slender form characteristic of the thoracic abdominal 

 region, viz. that part of such modified haemal or costal arch to which the term 

 ' vertebral rib ' is applied in comparative anatomy and the term ' pars ossea 

 costaa ' in anthropotomy : but, admitting the wider application of the term 

 ' rib ' to the whole haemal arch under every modification, yet the bony di- 

 verging and backward projecting appendage of such rib or arch is something 

 different from the part supporting it. 



Arms and legs, therefore, are developments of costal appendages, but are 

 not ribs themselves liberated : although liberated ribs may perform analo- 

 gous functions, as in the serpents and the Draco volans. 



If then the arms or pectoral members be modified developments of the 

 diverging appendage of the scapulo-coracoid arch, and if this be the haemal 

 arch of the occipital vertebra, it follows that the pectoral members are 

 parts of the head, and that the scapula, coracoid, humerus, radius and ulna, 

 carpals, metacarpals and phalanges, are essentially bones of the skull. 



The transcendentalism, therefore, which requires for its illustration that 

 the maxillary arches be the arms and hands of the head, meets its most direct 

 refutation in the fact of the diverging appendages, properly called arms and 

 hands, belonging actually to one of the modified segments of which the head 

 itself consists. 



The head is, therefore, in no sense a summary or repetition of all the rest 

 of the body: the skull is a province of the whole skeleton, consisting of a 

 series of parts or segments essentially similar to those of which the rest of 

 the skeleton is constituted. 



Most of the phrases by which Spix attempted to systematize and carry out 

 the repetition-hypotheses of Schelling and Oken, as applied to the osteology 

 of the vertebrate skull, may be similarly explained, and when well-winnowed 

 some grains of truth may be recovered. 



In denominating the palatine bone the ' hyoid bone of the face,' Spix en- 

 deavours to express a relation of general homology by a term which should 

 be confined to the enunciation of a special homology : but he adds " cornui 

 ossis hyoidei anteriori analogum," which shows an almost correct appreci- 

 ation of the serial homology of the palatine bone. It answers, however, in 

 the maxillary arch to the stylo-hyal or proximal element of the hyoidean 

 arch, not to the cerato-hyal or haemapophysial element ; and it needs only to 

 recognise the palatine as the ' pleurapophysis ' of its vertebral segment, to 

 appreciate all its true serial homologies. It might as well have been called the 

 'tympanic pedicle of the face,' the 'styloid process,' the 'scapula,' the 'vertebral 

 rib,' or the ' ilium — of the face', according to Oken's and Spix's faulty method 

 of expressing serial homological relations, since it holds in its vertebral segment 

 the same place which each of the above-named bones respectively does in its 

 segment. 



So also, with regard to the term ' os faciei iliacum ' applied by Spix to the 

 mastoid (s), the error lies not only in the application of a special term to ex- 

 press a general homological relation, but in the supposed serial homology so 

 expressed. Had Spix detected, in a cranial vertebra, the precise element 

 answering to that called 'iliac bone' in a post- abdominal vertebra, yet it 



