164 The Commercial Products of the Sea. 



the surface water during the winter immediately east and 

 west of the Bosphorus may not fall below 55° as. a 

 minimum. 



The northern shore of the ^gean Sea and the eastern 

 shore of the Adriatic Sea are populous with sponges, and 

 yet the former throughout its whole extent, and the latter 

 from Ragusa to Istria, have nearly the same average winter 

 temperature, and possess a colder climate in winter than 

 the coast of southern Italy or Spain, where no SpongicB 

 exist. Again, upon consulting the invaluable little Eckhe- 

 lian pamphlet, we find that the sponges correspond in 

 quality to this climatic change. The sort found at the 

 head of the .^Egean is said to be the Spongia officinalis 

 alone, and to have a "heavy, hard, close, very hairy 

 skeleton, often containing slime," and it is further added 

 that it is not much liked, and is usually fished with the 

 harpoon. The same species exist also alone at correspond- 

 ing localities along the shore of the Adriatic, and at the 

 extreme locality, the island of Istria, upon the limit of its 

 distribution, it is said to be very rare, the form to be ugly, 

 the skeleton hard, the colour dark. Farther south, along 

 the Dalmatian coast, it becomes abundant, finer in texture 

 and of a lighter colour, but it is still inferior to the more 

 southern or Levantine variety. In considering such classes 

 of facts, it must also be borne in mind that the habitat of a 

 certain sort of variety may largely determine the quality of 

 the skeleton, even where the temperature may be very 

 favourable. Thus, to the south of Quarnero, among the 

 islands, a much better quality of Spongia officinalis occurs 

 than in the milder sea about the Ionian Islands, which, as 

 Eckhel remarks, is probably attributable to the slimy 

 character of the bottom. 



The finest sponges in the Mediterranean, those of the 



