Page:The Zoologist, 4th series, vol 4 (1900).djvu/344

314 helping to keep the animal at the surface. Notwithstanding Rang's remark that the thread is doubtless formed of a special secretion, Eydoux and Souleyet think it probable that it consists merely of locomotory mucus, which, in these molluscs, may possibly possess special characters. Rang, it may be added, while examining spirit specimens, found, under the foot, a little glairy mass, which attached itself to the point of the scalpel, and was easily drawn out into a thread a foot and a half long; each specimen presented the same peculiarity, and Rang concluded that this was the substance from which the thread is made; it seems more probable, however, that the little masses were the remains of threads already spun, and perhaps reascended by the animal.

The above, the present writer believes, is all that is known of the spinning habits of Litiopa. These habits are certainly of a surprising character: the length of the apparently rapidly made thread, the animal's security upon it, and the facts that it can produce and afterwards ascend by it, not only in its native element, but also in the air, are points of special interest. As to the statements in the books, one may quote, for example, from Johnston's 'Introduction to Conchology':—