We may add, however, that other zoologists, and among them MM. Paul Gervais and Van Beneden, take a different view of the development of the sponges, and Dr. Johnston omits them altogether from his great work on "British Zoophytes." "If they are not the production of polypi," he says, "the zoologist who retains them in his province must contend that they are individually animals, an opinion to which I cannot assent, seeing that they have no animal structure or individual organs, and exhibit not one function usually supposed to be characteristic of the animal kingdom." Gervais and Van Beneden consider, as Milne Edwards does, that the embryos are at first movable, then fixed, many of them uniting together, and melting, as it were, into one common colony, which become a sponge, such as we see it. An isolated embryo might also, by throwing out germs, produce a similar colony, which would thus become a product of agamous generation. Thus it appears that Science is far from being settled in its views as to the organization and development of these obscure and complex formations; nor is it more advanced in its knowledge of the duration of life and the quickness of growth in sponges. It is agreed, however, on one point--namely, that the sponge-fisher may return to the same fishing-ground after three years from the last fishing. At the present time sponge-fishing takes place principally in the Grecian Archipelago and the Syrian _littoral_. The Greeks and Syrians sell the product of their fishing to the Western nations, and the trade has been immensely extended in recent times, when the sponge has become an almost necessary adjunct of the toilet as well as the stable, and in other cleansing operations. Fishing usually commences towards the beginning of June on the coast of Syria, and finishes at the end of October. But the months of July and August are peculiarly favourable to the sponge harvest, if we may use the term. Latakia furnishes about ten boats to the fishery, Batroun twenty, Tripoli twenty-five to thirty, Kalki fifty, Simi about a hundred and seventy to a hundred and eighty, and Kalminos more than two hundred. The operations of one of these boats fishing for sponges on the Syrian coast is represented in Plate II.