848 NATURAL HISTORY OF AQUATIC ANIMALS. 



subspecies mediterranea, some of which are of an inferior quality, occur on the eastern shore of the 

 Adriatic, on the coast of Greece to Asia Minor, and thence to Tripoli and Tunis. 



THE GRASS SPONGE SPONGIA GRAMINEA, Hyatt. 



" This is one of the Gras.s Sponges of commerce, and is perhaps one of the least variable of 

 all the species. . . . The general structure is coarser than in tubuUfera, and the interior is 

 exceedingly open, owing to the large size and central situation of the efferent canals. The form 

 is that of a truncated cone, fluted by deep furrows on the sides, and either infundibuliform or flat 

 on the truncated surface. The large excurrent orifices are all upon this surface, or in the depres- 

 sion which takes its place. The smaller apertures are situated on the sides, invariably in the 

 depressions between the ridges. The persistency of the former and of the latter ridges, and the 

 situation of the different kinds of orifices, are by far the most characteristic features of this species. 

 Notwithstanding these facts, and though I am obliged to describe this and some other forms as 

 distinct species, I have great doubts of the truth of the assumption. It rests upon the evidence 

 of many specimens, but they are all from one locality." 



This species occurs at Key West, Florida, where it grows abundantly on the coral reefs, either 

 on smooth bottoms or attached to corals or other Sponges, in three feet of water and deeper. 

 When living its color is black. 



THE SHEEPSWOOL SPONGE SPONGIA EQUINA, Schm., subspecies GOSSYPINA. 



' The typical variety of this species, usually called the Sheepswool Sponge, varies greatly in 

 form. All of these forms, however, are characterized by a peculiar surface. The skeleton rises 

 into large tufts over the entire surface, the larger oscula occupying the depressions between. 

 Sometimes these are very numerous, the whole interior being very cavernous, and sometimes the 

 structure is much denser, with fewer large openings and many small ones scattered between the 

 tufts. Occasionally the depressions are filled up on parts of the Sponge, and a surface is presented 

 having no large tufts, but only the small secondary bundles of fibers, which are especially charac- 

 teristic of this variety. The result of this structure is to leave great hollows or rather a net-work 

 of deep tunnels under the derm, which are apparent only after the drying of the specimens, when 

 they become exposed by the universal contraction and cracking of the skin. The color when 

 living is said by Dr. Palmer to be a shining black." 



The habits t of this species is Southern Florida and the Bahama Islands, where it grows in 

 from three to sixteen feet of water and deeper. The largest specimen examined measured about 

 nine inches high by thirty inches broad. The following five varieties are recognized by Professor 

 Hyatt: dendritica, porosa, alba, solitaria. and hirsute,. 



This is by far the finest of the American commercial Sponges, ranking much higher than any 

 of the other grades. It is also the one most eagerly sought for, the supply being quite unequal to 

 the demand. It takes the place of the finer Mediterranean grades for most purposes, and, though 

 not so fine in texture, is more durable than the Turkish Sponges. In the same species are placed 

 some of the best-known of the eastern grades, the so-called Horse Sponge, Venetian Bath Sponge, 

 and Gherbis Sponge, which occur in numerous places in the Mediterranean Sea. 



THE VELVET SPONGE SPONGIA EQUINA, Schm., subspecies MEANDRINIFORMIS. 



"This, the well-known Velvet Sponge of commerce, . . . differs from the preceding in 

 its extreme forms by the absence of the pointed bundles or tufts, and the fibers are also perhaps 

 slightly finer. The absence of the pointed tufts gives a smoother surface, since, as in the preceding 

 variety, these are mainly composed of coarse primary fibers loaded with foreign matter, whereas 



