ON THE VERTEBRATE SKELETON. 253 



The trunk of fishes, in respect of its viscera and the degree of development 

 of the endoskeleton, answers to the lumbar and caudal regions of air-breath- 

 ing vertebrates, where the vertebrae usually lose some of their elements, at 

 least as bones. The heart and respiratory organs are placed in the head of 

 the fish ; and it is only in this region that the vertebral segments attain to 

 typical completeness in that class. Geoffroy, in studying the special and 

 general homologies of the bones of the head of fishes, blends indiscrimi- 

 nately, as in the supposed typical vertebra from the tail, elements of the 

 dermoskeleton (suborbitals and lacrymals, e. g.) with those of the endo- 

 skeleton ; and also presses the capsules of the special organs of sense into the 

 composition of the seven cranial vertebras of his system. It needs only to 

 compare the synonyms of the elements of these vertebrae in Table III. to 

 perceive how impossible it would have been to have expressed the ideas 

 which I wish to expound and illustrate in this Report by the use of the names 

 for the vertebral elements proposed by Geoffroy, or of English equivalents. 

 The prefrontals, e. g. (no. 14), which I regard as the neurapophyses of the 

 nasal vertebra, are, according to Geoffroy, epials of the 2nd or labial vertebra 

 in the class of fishes ; but are epials of the 1st or nasal vertebra in the cro- 

 codile, according to the tables given in the ' Annales des Sciences,' t. iii. pi. 9, 

 and 'Atlas,' p. 44; whilst they are the perials of the 2nd vertebra in the 

 scheme of 1825, cited in the fifth column of Table III. 



I have deemed it requisite to enter the more fully into the grounds for 

 abandoning the analysis and nomenclature of the typical vertebra proposed 

 by Geoffroy, because they have received the sanction in this country of the 

 learned Professor of Comparative Anatomy at University College. Dr. Grant* 

 converts the French names into English equivalent phrases; 'cyclo-vertebral 

 element' for cycleal, 'perivertebral element' for perial, &c. ; and abandons 

 the advantage of a definite name, without remedying the disadvantages of 

 the double employment of the same names for two distinct elements, and of 

 the application of different phrases for the same element. If, for example, 

 the neural spine of the reptile or mammal be, in nature, the homologue of 

 the neural spine of the fish, then the latter is called an ' epivertebral element,' 

 whilst the former is called a ' perivertebral element.' If the dermo-neural 

 spines of the dorsal fin of a fish be, in nature, homologous with the fibro- 

 ligamentous tissue supporting the dorsal fin of the dolphin, then the term 

 ' epivertebral element ' is applied to a spine of the exoskeleton in the fish, and 

 to a spine of the endoskeleton in the mammal, which spine co-exists with such 

 dermal spine in the fish (see fig. 16). If the parapophysis or inferior transverse 

 process in the fish be a distinct element from the diapophysis or superior 

 transverse process in the mammal, the same phrase, ' paravertebral element,' 

 is applied to each. Dr. Grant, moreover, gives the same name, 'catavertebral 

 elements,' to the free vertebral ribs in fig. 28, B.g. p. 58, op. cit., as he applies 

 to the haemapophyses in the tail of the reptile or cetacean, in fig. 28, C. g. 

 Joe. cit. ; whilst Geoffroy applies the name ' cataaux ' to the sternal ribs, 

 and not to the vertebral ribs: and it is precisely with the sternal ribs that 

 the chevron bones in the tails of reptiles and cetaceans are homologous, and 

 both are, therefore, the ' haemapophyses ' in my system. The transference 

 of the term ' catavertebral elements ' (for cataaux}, from the ' cotes sternales ' 

 to the pair of ribs extended from the ends of the parapophyses of the abdomen 

 of fishes, is a deviation from the original vertebral system of Geoffroy, which 

 seems to lead further away from nature. If it is meant that the outstretched 

 parapophyses in the diagram of the abdominal vertebra of a fish (fig. 28, B.f.f. 

 loc. cit.), and which are there called ' paravertebral elements,' are the homo- 

 * Outlines of Comparative Anatomy, 1835, pp. 57-59. 



