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for three or four years, procured all the specimens which I thought would 
throw any light upon its history. My endeavours would, however, I 
suspect, have been attended with very little success, if my very kind 
triend, Mr. Townsend, had not availed himself of his vicinity to Bradford, 
and favoured me Avith such specimens as he considered would be most 
likely to facilitate my inquiries. 
The vertebral column of this species, at least in such specimens as have 
come under my observation, does not appear to be marked by any very 
remarkably distinguishing character. The vertebree are, indeed, thin, but 
not so much so as those of the last species ; the articulations are particu- 
larly nicely fitted, and, in consequence, the whole column has a very neat 
and elegant appearance, as may be seen in the representation of this part 
of the animal, Plate XVI. Fig. 1. 
At the superior termination of this column, the vertebrae, for the space 
of about half an inch, and for about the number of eight or nine, 
comprised in that space, gradually increase in their diameter, but still 
retain, very nearly, the same degree of thickness, as may be seen in the 
specimen, Plate XVI. Fig. 2. 
Beyond this point the vertebrae increase in their diameter much 
more suddenly, have a much larger central foramen, and acquire more 
than double their former thickness. These vertebrae are generally about 
six in number, and occupy about twice the length of the former, 
Plate XVI. Fig. 7. These, when separated, are found to differ very 
materially from the preceding vertebrae : their inferior surfaces are concave 
to a considerable depth, whilst their superior surfaces, so far from 
possessing a corresponding degree of convexity, are, in general, but 
slightly rounded, and are very frequently quite flat, Plate XVI. Fig. 3. 
Hence, between each of these vertebrae, a central circular space must 
exist, deeper in its centre than at its margin ; its magnitude, of course, 
depending on the degree of disparity existing between the opposed 
surfaces of the united vertebrae. 
To these succeeds a body of a different form, in which the general 
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