Sponge and the Sponge Fisheries. 167 



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 



