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occipital vertebre of the carp, and from the centrums of certain cer- 
vical vertebrz of fishes and birds, and which Dr. Melville had trans- 
ferred to his diagram of a thoracic vertebra, and made it to consist 
of three distinct elements. Professor Owen stated that he had not 
presumed to depart wholly from nature, either by addition or sub- 
traction, in the figures of the typical vertebre, in his work (p. 81, 
fig. 14, p. 82, fig. 15) criticised by Dr. Melville; and that he knew 
of nothing in nature which corresponded with Dr. Melville’s diagram, 
showing distinct hemapophyses and a hemal spine coexisting with 
vertebral ribs, sternal ribs, and sternum, in the same segment. On 
the principles on which Dr. Melville had constructed his ideal ver- 
tebra, viz. by the addition of mere adaptive processes of the centrum, 
exaggerated and artificially subdivided, to true and constant vertebral 
elements, such ideal vertebra might with a good reason be made 
symmetrical by the addition of a second concentric neural arch, as in 
Professor Owen’s sketch of the human parietal vertebra, to the true 
expanded neural arch, and in his opinion such superadded internal 
neural arch might, with as good reason, be viewed as the true neur- 
apophyses and neural spine, and had as good title to be diagramati- 
cally represented as subdivided into those three separate elements, 
as the second internal hemal arch, which Dr. Melville had super- 
added to his (Professor Owen’s) figure of the second form of the 
typical vertebra (On the Archetype, &c., p. 82, fig. 15). Such an 
‘ideal vertebra’ would then truly exhibit what Dr. Melville had de- 
fined as ‘‘ the most complete possible vertebra,” and what Mr. Mac- 
lise called ‘‘ the plus vertebral quantity.” 
Dr. Melville rejoined by reiterating his conviction that his ‘ ideal 
vertebra’ was the true one, and would ultimately be accepted as such 
by all anatomists. 
