48 
APPENDIX I. 
The first rib is shorter than the rest, and they become gradually longer to the tenth and eleventh, which 
are the longest; they afterwards become gradually shorter to the twentieth, which is nearly of the same 
length as the first; so that the ribs on each side, when extended, form an oval figure, of which the spine is 
the middle line or long axis. 
In the extended state of the ribs, the skin of the back is brought over them, forming the hood; and in their 
depressed state the hood disappears. 
The ribs are raised by four sets of muscles : one set from the spine to the upper edge of each rib ; a second 
set from the ribs above, passing over two ribs to the third rib below ; another set have their origin from 
the rib above, pass over one rib, and are inserted into the second below ; and a fourth set pass from rib to rib. 
The combined effects of these four sets of muscles, raises and extends the ribs ; their direction and ap- 
appearance is so distinctly seen in the annexed figures, as to make a more particular description in a paper 
of this kind, unnecessary. 
The skin of the back is brought forwards on the neck, by a large set of very long muscles going off from 
each of the first twenty ribs on each side, a quarter of an inch from their head by a tendinous origin, which 
soon becomes fleshy ; the longest of these muscles is two inches long ; they are inserted into the skin ; and 
when the ribs have been first extended, have the power of bringing the skin forwards to a great extent. By 
these means the hood is formed. 
To depress the ribs, and restore the parts to that state in which the neck of the animal does not appear 
disproportionally protuberant, but of the same size as the rest of the snake, there are three sets of muscles : 
one set goes from the vertebrae of the neck to the lower edge of each rib ; but, to give these muscles a 
greater length of fibre, they are not inserted into the rib immediately above the vertebrae, but pass upwards 
and outwards over three ribs, and are inserted into the fourth at the middle part of it. These muscles 
become antagonists to those which raise the ribs. 
The second set arises from the points of the ribs ; and each muscle goes to be inserted into the skin nearer 
the head, counteracting the muscles which bring the skin forwards, and drawing it by their action back 
again. The third set goes from the root of one scutum to the root of the scutum immediately above it, so 
as to bring it down upon the other. 
The object of the present paper being to explain the mechanism upon which the hood, the peculiar 
characteristic of this species of snake, depends, it is not meant to enter into the uses for which the hood is 
intended. It may not however be improper to observe, that the expansion of the ribs answers no good pur- 
pose respecting the lungs, since they are not so situated in this animal as to receive any advantage from it ; 
but the gullet, where it passes down along the neck, admits of great expansion; and the extended state of 
the ribs, at the time the animal is employed in catching its prey, may give to the gullet a facility of being 
dilated for the reception of the food. 
EXPLANATION OF THE FIGURES. 
PLATE VII. 
Fig. 1, A side view of the head and neck of the Cobra de Capello, drawn from the living animal. 
Fig. 2 ,. A back view of the hood. 
Fig. 3. A front view of the hood. 
PLATE VIII. 
Fig. 4. A back view of the neck in its expanded slate; the external skin being dissected off, and turned 
aside to shew the muscles which raise the ribs, and bring the skin forwards towards the head. 
This view is intended principally to exhibit the muscles which raise the ribs, and those which, 
when the ribs are raised, act upon the external skin, and bring it forwards. 
AA. The scales on the head of the snake. 
BB. The eyes. 
