FEDERAL FISH FARMING 



443 



THE UNDER SURFACE OF A SHEEl'SWOOL SPONGE 



Not over j8 months old ; PTOwn on a cement disk at Anclote Key from a cutting. Weight, 

 dry and thoroughly cleaned, i^ ounces. The root or under surface of natura sponges wliicn 

 grow on ro-'gh rock hottoms. as on page A^g, and which must be torn from the rock, is raw, 

 like the inferior of the soonge. and therefore is the weakest and least durable part ot ttie 

 sponge. The root of cultivated soonges, on the contrary, is the strongest part ot the sponge 

 as contact with the flat cement disk on which the cutting is planted develops a close and sott 

 felt, as shown in this illustration. 



lakes. The importance of this work is 

 urgently insisted upon by the National 

 Pearl Button Manufacturers' Association, 

 which embraces practically the entire 

 capital invested in the business. 



STUDY OF DISEASES OF THE FISH 



In the field of fish diseases great prog- 

 ress has been made in the extension of 

 knowledge of the causes of many of the 



fatalities which sometimes make a clean 

 sweep of the hatcheries and which here- 

 tofore could not be adequately coped with 

 because their etiology was not under- 

 stood. The services' of the scientific 

 statT in this regard have been not only of 

 great benefit to the government, but are 

 highly regarded and frequently availed of 

 by state and private fish-culturists. 

 'Among the direct tnaterial aids rendered 



