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 vertebra 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 vertebre of his system. It needs only to 
compare the synonyms of the elements of these vertebre 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 Ist or nasal vertebra in the cro- 
codile, according to the tables given in the ‘ Annales des Sciences,’ t. iii. pl. 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 cycléal, ‘perivertebral element’ for périal, &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 fia 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. cat., as he applies 
to the hemapophyses in the tail of the reptile or cetacean, in fig. 28, C. g. 
loc. 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 ‘ hemapophyses’ in my system. The transference 
of the term ‘ catavertebral elements’ (for cataaux), from the ‘ cdtes 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. 
loe, cit.), and which are there called ‘ paravertebral elements,’ are the homo- 
* Outlines of Comparative Anatomy, 1835, pp. 57-59. 
