404 BULLETIN OF THE BUREAU OF FISHERIES. 
This paper, in conjunction with another on sponge culture,? is designed to 
furnish a brief, but fairly comprehensive, review of present knowledge of com- 
mercial sponges, the geographical distribution of the fisheries, the methods 
employed, the effects of those methods upon the natural beds, and the meas- 
ures which appear to be necessary for the protection and conservation of the 
supply. 
Concerning the qualities and the characteristics that distinguish sponges 
of different grades and values, the consumer is probably less informed than 
in respect to any other natural product in general use, and he is frequently 
imposed upon. In many cases it is difficult for even an expert to identify the 
different local varieties, though there is much difference between them in 
the qualities that fix their value for practical use. The distinctions by which 
the various grades can be recognized are, moreover, such as to be difficult or 
impossible of expression in words. For these reasons the illustrations of this 
paper have been prepared, with especial care, to supplement the descriptions. 
The sponges pictured are typical specimens of the numerous local varieties 
and without exception represent sponges now on the market. 
As the purposes of the paper are mainly practical and economic, the 
discussion of the scientific status of the various kinds of commercial sponges, 
their general biology and morphology, has been reduced to the minimum nec- 
essary for a proper understanding of their nature and the problems which 
must be solved before the regulation of the beds can be placed on a rational 
and effective basis. The question of the scientific classification of the com- 
mercial varieties will be taken up some time in the future, when the accumula- 
tion of material and certain experimental data may offer some guarantee of 
better results than have been attained previously. The subject is one of 
extreme difficulty, and it is not believed that it can be successfully attacked 
without the assistance furnished by a well-equipped laboratory in the vicinity 
of the sponge grounds. 
I. THE LIVING SPONGE. 
To most persons familiar only with the sponges of the shops, the animal as 
it comes from the sea would be entirely unrecognizable. (Plate xxvu.) It is 
a solid looking, rather slimy feeling, fleshy body, varying in color from light- 
greyish yellow through a considerable range of browns to black, and in form 
either cup-shaped, spheroidal, or cake-shaped, according to the species, its age, 
or the environment in which it grew. In general, in appearance and consist- 
ency and the manner in which it cuts with a knife, a living sheepswool sponge 
is not unlike a piece of beef liver, perforated with holes and canals. 
@Moore, H. F.: A practical method of sponge culture, Proceedings International Fishery Con- 
gress, in Bulletin U. S. Bureau of Fisheries, vol. xxv, 1908, p. 545-585. 
