a new Fossil Animal. 
585 
cess, like the three last dorsals in the Crocodile and the whole series 
in most other Saurians. The pointing upwards of the transverse 
processes in the middle of the series seems intended to give a wider 
sweep to the ribs flanking the thorax and abdomen. 
All the changes last described are represented in the accompany- 
ing figures, of which fig. 6 represents the form of the vertebras frpm 
the 1 8th to the 22d, where the margin of the suture forms a re- 
markably prolonged sinus. Fig 7 A, and fig. 7 B, represent the 
incipient appearance of the transverse process about the 22d ver- 
tebra. The body of this vertebra is shewn first separately, and 
then with the annular part attached. Fig. 8 shews three vertebrae 
nearly succeeding this, but from another more perfect and aged spe- 
cimen. Fig. 9 A, and fig. 9 B, exhibit the middle dorsal vertebrae 
with and without the annular part, to shew the form of the suture 
and its different contour from that in the cervical and first dorsal ; 
the posterior dorsals differ only in having the transverse process 
less elevated, and did not therefore require representation. 
The lumbar and caudal vertebrae appear to differ in form from 
one another only in a less inflection of the lower margin, for the 
purpose shortly to be mentioned ; they are however very distinct 
from all the others ; they have no regular transverse processes, but, 
instead of them, two separate bones flattened at the extremities, and 
articulated into a socket near the upper part of the sides of the 
bodies of the vertebrae ; their position is exactly horizontal. We 
have before observed that the Ichthyosaurus appears to have had 
similar bones. The lower margin of these vertebrae on the pos- 
terior extremity is inflected so as to form two regular indentations, 
exactly as in the Crocodile, for the reception of the chevron- shaped 
bone beneath the tail. All these circumstances are represented in 
fig, 10 A, 10 B, 10 C, which exhibit one of the early caudal ver- 
4 E 2 
