414 Dr. Bancroft on Jamaican Fishes, &c. 
better epithet than the latter, when its peculiar structure shall have been 
explained. Neither does the great Cuvier appear to have studied it 
(probably from the want of a good specimen) as is evident from the 
doubt he entertains as to its modus operandi; ‘le poisson se fixe aux 
“< differents corps, soit en faisant le vide entre les lames transversales, soit 
‘* en accrochant les épines de leur bords.’’ Bosc is the only one who 
has expressed a just notion on this subject; ‘* je reste persuadé que c’est 
“< en faisant le vide que ]’Echeneis se fixe,’’ (Deterville’s Dict. d’Hist. 
Nat. t. 10, p. 46.) but he has left us nearly as much in the dark as to the 
anatomy of the part as his predecessors. Yet the whole of its conform- 
ation is most curious. After dissecting such a portion of it as exhibited 
its structure, I made sketches of the various bony and cartilaginous pieces 
and of the several sets of muscles that act between them, and drew up 
some account of its structure. But having afterwards succeeded in 
getting a second specimen of the fish, I have determined to send it to 
Mr. Bennett’s (and, if necessary, to Mr. Yarrell’s) charge, and to request 
them to undertake a labour for which they are far better qualified: and 
although I have since obtained a third specimen (which, with the first, is 
sent in the breaker) yet] have put into the cask with these a spare disk, 
which I partly dissected, that it might not be necessary to mutilate either 
of those specimens by removing its disk for the purpose of anatomical 
examination. The organ will be found nearly as complicated as the 
spine and the ribs in vertebrated animals, and there is some similarity in 
the play of the parts on each other so far as relates to the dorsal surface ; 
yet the whole mechanism is singularly different, (one single transverse 
piece for instance supplying the place of one pair of ribs and of the body 
of the vertebra belonging to it,) and at the same time beautifully simple 
and efficient. The outer border of the disk would of itself suffice for 
mere adhesion to the surface on which it is applied, when a perpendicu- 
lar force is exerted to pull it off, as in the case of the wet leather suckers 
that boys play with: but it offers no resistance, as I have found on trial 
repeatedly, to a force parallel to the surface, which causes the disk to 
slide over it in all directions. The mechanism of the amine, however, 
within the disk effectually supplies that deficiency. In their state of 
