Sir Evfrard Homf/s account, &c. gig 
The structure of the vertebrae explained in the former 
paper, made it evident, that the animal in its mode of pro- 
gressive motion resembled fishes ; it could not, however, be 
determined that it was in ail respects a fish, till the articulations 
of the ribs with the vertebrae, and the bones of which the 
pectoral fin is composed, had been examined. 
In all animals that breathe by means of lungs, each rib, to 
admit of its being raised and depressed, is articulated both 
to the body and the transverse process of the vertebrae ; but 
in fishes, the ribs requiring no such motion, are only connected 
to the bodies of the vertebrae laterally, so as not to interfere 
with their extensive motion on one another. In this animal, 
the ribs are placed in this respect like those of fishes ; they are 
uncommonly large, and the chaetodon from Sumatra, the ske- 
leton of which is described by Mr. Bell in the first part of 
the 83d vol. of the Philosophical Transactions, is the only fish 
I know of in which the ribs bear the same proportion to its 
size. The form of the scapula, as well as of the bones of the 
pectoral fin, is entirely different from those of the whale, but 
bears a resemblance to that of the same parts in the shark, so 
that it is only necessary to compare them together as repre- 
sented in the annexed plates, to recognise their similarity. 
The other circumstances that confirm this skeleton being 
that of a fish, are the bones in a growing state having no 
epiphyses, as will appear from the first bone of the pectoral 
fin, which is represented of its natural size, having hone, 
although when compared with the single vertebra, also repre- 
sented of its natural size, the fin must have belonged to a 
growing animal ; the ribs having been grooved longitudinally 
by pressure, showing the softness and toughness of their 
