n 
lower ends of two glandular — ^like bodies, which I 
suppose to be the ovaria. The posterior part of each 
sac, or lobe, is bound down to the root of the mesen- 
tery, except at its lower end, where it is entirely un- 
contined by this mesenteric structure, and floats loose 
in the cavity. This circumstance seems to have es- 
caped the notice of Dr. Garden, who says, that the 
lungs are tied down, through their whole length. Mr. 
Hunter, who speaks of these organs in a very brief 
way,# says nothing relative to the manner in which 
they are attached to the mesentery. 
Each sac of the lungs is convex, or rounded, ex- 
teriorly, so as to correspond, both in shape and size, 
with the abdominal cavity; and is flattened, or par- 
tially concave, on the inner side, so as to contain the 
diflerent viscera : for the whole of the viscera are in- 
cluded between the two sacs of the lungs. 
I have said, that the lungs of the Siren are uncom- 
monly capacious. In illustration of this observation, 
I may now remark, that in the large Siren, which I 
dissected, the entire length of which was thirty 
inches, the longest sac of the lungs was eighteen 
inches in length, and the greatest diameter of either 
of the sacs; not less than three quarters of an inch. 
The texture of the lungs is membranous, and the 
membrane is extremely thin, delicate, and pellucid. 
The whole surface of these organs is covered with 
numerous ramifications of blood-vessels, which give 
* The lungs are two long bags, one on each side, which begin 
just behind the heart, and pass back through the whole length of 
the abdomen, nearly as far as the anus. They are largest in ihe 
middle, and honey-combed on the internal surface through their 
whole length. Philosophical Transactions, &.c. 
3 
