1 62 The Commercial Products of the Sea. 



dance in such places. This entirely agrees with obser- 

 vations made upon many species on the North American 

 coast of Chalinince and Halichondrida. Constant reference 

 to physical influence is also noticeable in the map prepared 

 by Von Eckhel, and in the method of classification adopted 

 by him. The marketable qualities are described as " sorts," 

 and the difl"erent " sorts " designated by letters, as " sort A," 

 ''sort B," and so on. These sorts he has found it most 

 convenient to arrange according to localities, and thus under 

 some " sorts " we have all the three species represented ; 

 all, however, from the same place, and all having some 

 local peculiarity which makes them either of superior or 

 inferior quality. The author also frequently refers to the 

 slimy character of the bottom as a reason for inferiority 

 or dark colour. On the American side of the Atlantic 

 this is also shown by the great difference in point of colour 

 and fineness between the Nassau and Key West sponges. 

 The former are lighter coloured, finer, more elastic, and 

 more durable, than the same species at Key West, where 

 the colour is so dark that it designates at once the locality 

 from which the specimen came. 



Again, the shallow-water sponges are coarser than the 

 deep-water forms. This is probably due, in part, as in 

 other species, to the quantity of sediment, which is of 

 course less in deep than in shallow water, as, for example, 

 at Key West in the winter time. Mr. Saltonstall, who made 

 inquiries among the spongers, states that no fine qualities 

 of any sponges are found within the limits of the milky 

 water, but all the finer qualities of the marketable kinds in 

 the deepest water in which the species occur, except, perhaps, 

 in the case of the reef sponge. Glove, reef, and hard head 

 are fished in shallow waters, greatest depth two fathoms, and 

 the other and generally finer marketable varieties from two 



