The fine soft Syrian sponge is distinguished by its lightness, its fine flaxen colour, its form, which is that of a cup, its surface convex, voluted, pierced with innumerable small orifices, the concave part of which presents canals of much greater diameter, which are prolonged to the exterior surface in such a manner that the summit is nearly always pierced throughout in many places. This sponge is sometimes blanched by the aid of caustic substances, acids, or alkalies; but this preparation shortens its duration and changes its colour. This sponge is specially employed for the toilet, and its price is high. Those which are round-shaped, large, and soft, sometimes produce as much as five or six pounds. The _Fine Sponge of the Archipelago_ is scarcely distinguishable from that of Syria, either before or after being cleansed; nevertheless, it is weightier, its texture is not so fine, and the holes with which it is pierced are at once larger and less in number. It is nearly of the same country as the former, in fact, the fishing extending along the Syrian coast as well as the littoral of Barbary and the Archipelago. The _Fine Hard Sponge_, called Greek, is less sought for than either of the preceding; it is useful for domestic and for certain industrial purposes. Its mass is irregular, its colour fauve; it is hard and compact, and pierced with small holes. The _White Sponge of Syria_, called Venetian, is esteemed for its lightness, the regularity of its form, and its solidity. In its rough state it is brown in colour, of a fine texture, compact and firm. Purified, it becomes flaxen and of a looser texture. The orifice of the great channels which traverse it are edged with rough and bristly hairs. [Illustration: (From Dr. Grant.) Fig. 11. _Spongia oculata_, showing the orifices and currents outwards. 2. Anastomosing horny substance of _Spongia communis_. 3. Siliceous spiculum of _S. papillaris_. 4. Of _S. cineria_. 5. _S. panicea_. 6. Calcareous spiculum of _S. compressa_. 7. Transverse section of a canal of _S. papillaris_, showing the structure of the ova passing along the canal. 8. Ovum of _S. panicea_ seen laterally--the ciliæ anterior. 9. The same seen on the end, with a circle produced by the ciliary action. 10. Young _Spongia papillaris_.] The _Brown Barbary Sponge_, called the Marseillaise, when first taken out of the water, presents itself as an elongated flattened body, gelatinous, round in shape, and charged with blackish mud. It is then hard, heavy, coarse, but compact, and of a reddish colour. By a simple washing in water it becomes round, still remaining heavy and reddish. It presents many gaps, the intervals of which are occupied by a sinuous and tenacious network. It is valuable for domestic use, because of the facility with which it absorbs water, and its great strength.