coloured and coarse variety of the Spongia equina is obtained, called the gerbis sponge.

The distribution indicates the naturalness of the three species, and shows also that the dealers have to do with a vast variety of forms. They can, however, pick out the three species and their varieties without hesitation, and I was amused and interested at finding that the method pursued was precisely similar to that which I had been

Outer surface of different kinds of sponge (natural size). A, Cup-shaped variety; B, honeycomb sponge; c, toilet sponge; D, Bahamas sponge, partly in sections, showing projecting extremities and internal tubular character. obliged to adopt in distinguishing empirically the various sub-species and species of Spongia. They are led mainly by the general aspect of the surface.

This has a distinct

appearance in every species, and though much altered by the greater or less development of superficial tufts, is much more constant than any other character. This is due to

the fact that the surface takes its aspect largely from the number, distribution, and size of the pores, cloacal orifices, superficial canals, and primary fibres. These characteristics, of course, are directly correllated with all that is important in the internal anatomy of the animal, and should therefore be more constant than the length, form, or composition of the tufts of fibres, or the shape of the whole, which are capable of great modification, according to the locality in which the specimen may be found. The forms of Spongia officinalis may vary from cup-shape to fistular, and to irregular or lump-like. The latter are usually coarser and looser in texture, the superficial tufts are longer and more numerous, and they approximate more closely to the coarser varieties of sub-species tubulifera of the Caribbean Sea in the external aspect of the surface and the apertion of the interior, than the finer varieties.

The texture of the poorest variety of the Mediterranean sponges is, however, always better for domestic purposes than the best of the corresponding American varieties, being firmer and more elastic; and it is also to be remarked that the last never have the cup-shape, which is so common in the sub-species Mediterranea, and that the fistular form takes its place. The forms of Spongia agaricina, sub-species Zimocca, vary from saucer-shape to irregular, lump-like growth. As in the Spongia officinalis, it may be shown that these aberrant forms are quite similar to the aberrant or formless varieties of the sub-species punctata of Florida, as regards the aspect of the surface; but these also are nevertheless much finer than the finest varieties of the latter. Here, again, the platter or saucer shape, which is

a modification of the cup-shape, is absent. Spongia equina exhibits similar degrees of variation in the texture of the surface and the form. There are no proper cup-shaped specimens among the American varieties of sub-species gossypina, but in place of these the fistular form. These occur generally associated in clumps, more or less densely filled up into heads, and solid, but sometimes the tubes are almost isolated. The younger specimens of this species have a very loose and open texture, due to the approximation and large size of the openings, and to a less degree this is also to be remarked in the gerbis sponge. The former approximate in aspect to the coarser qualities of the American species, and so also does the latter, which has very nearly the same colour and aspect as the darkcoloured Key West specimens, but it is not so coarse or dark. It seems, then, that there are three sub-species of commercial value in the Mediterranean, which find their way into the New York and European markets. The coarsest varieties of the European sponges are finer, firmer, and more elastic than the finest of the corresponding American sub-species. This is directly traceable to the larger amount of foreign matter included in the primary threads, the looser mesh of the tissue; the fibres are also comparatively coarser and the large cloacal channels more numerous throughout the mass.

Thus the different varieties of sub-species gossypina differ in an exactly similar way from each other, and from the third form, sub-species cerebriformis; they differ in texture, in surface, and also in habitat, the finer kinds, as stated previously, being found in the deeper water, equally removed from excessive heat and excessive sediment. These three sub-species run together by means of specimens of the coarser varieties, which cannot be distinguished

from each other with any certainty, in the same manner as the corresponding sub-species in the Mediterranean and Caribbean Seas were connected, through the coarser, and not by the aid of the finer varieties. It is evident, however, that besides the general differences previously noted, the cup-shape form is not found in the American subspecies, whereas it is the prevalent form of the Mediterranean sub-species. A cursory examination of a large collection will, however, satisfy any one that the shape does not necessarily correllate with a finer or a coarser skeleton, but probably with a more or less extended base of attachment and local peculiarities, such as currents, and the kind of bottom, etc., which have not been investigated in this connection.

The American Sponge Fisheries.-The coarser descriptions of sponge entering into commerce are procured about the Bahamas banks and the coast of Florida.

Sponge fishing is said to have become a very profitable business in the neighbourhood of Key West, Florida. The article is mostly procured there by the natives of the Bahamas, who best understand the business of sponges ; and its principal grounds are Rock Island, a scope of land 30 miles long by seven miles broad, lying off Taylor county and 60 miles north-west from Cedar Keys; thence from the mouth of the Withlacoochee, past Martin's Reef to near Tampa Bay, a distance of perhaps 300 miles.

The number of small schooners engaged is between 75 and 100, with an average of from 5 to 15 men to each, and an average of three dingies to each vessel. The vessels built for the purpose are half oval-shape, and as flat as is consistent with due regard to sailing qualities. Dingy, or dincey, is the small boat used to gather the