The spawn of the squid (_Loligo vulgaris_) consists of dozens of semi-transparent, gelatinous, slender, cylindrical sheaths, about four or five inches long, each containing many ova embedded in it, and all springing from one common centre, and resembling a mop without a handle. Johann Bodasch, Professor of Natural History at Prague,[22] calculated that one of these mop-like masses contained 39,766 ova; and by counting those embedded in ten of the long gelatinous, finger-like processes, and weighing them and the remainder, I have verified his estimate, and computed that in the specimen which was the subject of my investigation there were 42,000 perfect young squids. It is evident that comparatively few of them live to arrive at maturity, or the sea would teem with them; and in every existing aquarium it has been found impossible to rear the young cephalopods hatched there. I have never seen these “sea-mops” attached to anything, and the pelagic habits of the calamaries render it probable that they are left floating on the surface of the sea. A remarkable organ with which some of the cephalopoda are provided is a sac, popularly called the “ink-bag,” in which is stored a deep black secretion, which they are able to employ at will as a protection from rapacious enemies. On the approach of a suspected foe, the animal discharges a quantity of this dense fluid, which renders turbid the surrounding water, and thus enables its owner to escape in the obscurity. There is a communication between this ink-bag and the funnel or locomotor-tube, already described; so that when the ink is ejected, it is forcibly emitted with the stream of water which produces its rocket-like, backward motion. The very effort for escape thus serves the double purpose of propelling the creature away from the danger, and discolouring the water in which it moves. Oppian has well described this:— “Th’ endanger’d cuttle thus evades his fears, And native hoards of fluids safely wears. A pitchy ink peculiar glands supply Whose shades the sharpest beam of light defy. Pursued, he bids the sable fountains flow, And, wrapt in clouds, eludes th’ impending foe. The fish retreats unseen, while self-born night With pious shade befriends her parent’s flight.”