It appears from this account that the male Calamary (at a certain time of the year only) has a bag wherein the milt-vessels are contained, and that the female has no such bag. Since therefore the bag of our Polypus is found in the same situation as that of the Calamary, (which is also a kind of Polypus) we may suppose it to be the milt bag, and that our Polypus is a male, taken at a time when the milt was ready for ejection. In the dried specimen at the British Museum, and also in the other specimens, there is the same opening, with the pipe that rises above it towards the arms, but not the least appearance of the bag in question: they are therefore probably females, or if males, were caught before such bag was formed.
[Fig. 3.] presents another view of this Polypus, its arms extended circularly with their under-sides next the eye, and the body so disposed as to shew the transverse opening a, the oval bag issuing therefrom b, and the pipe rising upwards towards the arms c.
[Fig. 4.] shews the Polypus with its transverse opening and the pipe rising therefrom, but without the oval bag; it is figured thus by Rondeletius and Gesner, and the specimen at the British Museum has also this appearance. It is here shewn with the arms extended forwards. K is a magnified figure of one of the acetabula, or suckers; of which there are two rows on each arm of this Polypus, as before described.
Mr. Needham, in his description of the suckers of the Calamary, (which he had many opportunities of examining whilst alive, and whose mechanism is probably the same as in those of our Polypus) informs us, “that the action of the suckers depends partly on their shape, which, when they are extended resembles nearly that of an acorn-cup, and partly upon a deep circular cartilaginous ring, armed with small hooks, which is secured in a thin membrane something transparent, by the projection of a ledge investing the whole circumference about the middle of its depth, and not to be extracted without some force. That each sucker is fastened by a tendinous stem to the arm of the animal: which stem, together with part of the membrane that is below the circumference of the cartilaginous ring, rises into and fills the whole cavity when the animal contracts the sucker for action. In this state whatever touches it is first held by the minute hooks, and then drawn up to a closer adhesion by the retraction of the stem and inferior part of the membrane, much in the same manner as a sucker of wet leather sustains the weight of a small stone.” Vid. Microscopical Discoveries, p. 22.
M shews one of the cartilaginous rings armed with small hooks, of its real size. The ring this is drawn from was taken out of a large sucker of a larger Polypus, and is presented herewith.
By these suckers the Polypus can fix itself to rocks, and prevent its being tossed about in storms and tempests; but their principal use must undoubtedly be to seize and hold its prey: and to this purpose they are most admirably adapted; for when they are all applied and act together, unless the Polypus pleases to withdraw them, nothing can get from it whose strength is insufficient to tear off its arms. Something like these suckers is found by the microscope in the minute fresh water Polype, whereby it is able to bind down and manage a worm much larger and seemingly stronger than itself[161]. In like manner the stella arborescens (which may also be called a Polypus), though it has not suckers, yet by the hooks along its arms, and the multiplicity of their branchings, which have been counted as far as 80,000, it can, by spreading its arms abroad like a net, so fetter and entangle the prey they inclose when they are drawn together, as to render it incapable of exerting its strength: for however feeble these branches or arms may singly be, their power united becomes surprising. And we are assured nature is so kind to all these animals, that if in their struggles any of their arms are broken off, after some time they will grow again; of which a specimen at the British Museum is an undoubted proof; for a little new arm is there seen sprouting forth in the room of a large one that had been lost.
It is evident from what has been said, that the Sea Polypus must be terrible to the inhabitants of the waters, in proportion to its size (and Pliny mentions one whose arms were thirty feet in length); for the close embraces of its arms and the adhesion of its suckers must render the efforts of its prey ineffectual either for resistance or escape, unless it be endued with an extraordinary degree of strength.
Sea Polypi are frequent in the Mediterranean: but Mr. Haviland of Bath, to whom we are obliged for this, which is of a different species, thinks it came from the West Indies, where it is called a Cat-fish. That like it in the British Museum also came from thence.
As the Polypus I have endeavoured to describe is much contracted by lying long in spirits, and dissection would destroy a specimen well worth preserving, I hope to be excused if this account should be found deficient in several particulars, or chargeable with some mistakes.
Permit me the honour to be,