vi 



only the name of the bone, but the views of its homology as 

 indicated by the names or phrases designating it in some of the 

 most esteemed Works on Osteology. Names of bones and parts, 

 applicable to the Vertelrata generally, are, in this Catalogue, applied 

 to the same bones or parts in the Human Skeleton. The ' os innomi- 

 natum ' is a single bone in adult Man ; but special names are given, in 

 Human Anatomy, to the three distinct bones of which it originally 

 consisted : these remain distinct in many of the lower animals. As 

 the constituents or ' elements ' of other Human compound bones, such 

 as the ' occipital,' ' temporal,' ' sphenoid,' remain ununited in many 

 lower Vertebrata, and have received distinct names, these names are 

 also applied to the corresponding bones which, when united, form 

 those compound bones in Man. 



The power of identifying any bone, under the variations of con- 

 figuration which it presents in the different classes of Vertebrate 

 animals, depends upon the principle that the skeletons of the Verte- 

 brata consist of segments, each of which is constructed according 

 to the pattern of a vertebra. And in order to facilitate the recog- 

 nition of these divisions in the different classes of Vertebrata, the 

 labels on the component portions of the same segment are of the 

 same colour. Thus, in the skull, the labels on the hindmost or occi- 

 pital segment are ' yellow,' on the next or parietal segment ' green,' 

 on the frontal segment ' blue,' on the nasal segment * red.' The 

 component portions or ' elements ' of each segment or * vertebra ' 

 are distinguished by numerals, or, in some instances, indicated by 

 the initial letters of their names. For example, c is the centrum ; 

 w, the neurapophysis ; pi, the pleurapophysis ; h, the hsemapophysis : 

 and besides such proper elements which are developed from distinct 

 centres of ossification, the more constant processes which grow out 

 from them are indicated in some instances by the initials of their 



