UTILIZATION OF THE SKINS OF AQUATIC ANIMALS. 347 

 SKINS OF SHARKS, RAYS, AND DOG-FISH. 



Tho skins of sluirks, rays, and doo-tish are connnonly xory rouoh and 

 studded with numerous horny tul)er('ulous niarkinos or protu))erances. 

 Some have small ini])ricated and triangular scale-like tubercles; others 

 unimbricated and nearh^ rhomboid, which in one species are ranged 

 near each other in quincunxes, or they may be quite square, compact, _ 

 and comparative!}' smooth on top. These protuberances are usuall}^ 

 tirmlv fixed to the skin so that the}' are not easil}' separated therefrom. 

 The}^ are rough and hard and take a polish almost equal to stone. 



These skins, like those of all cartilaginous fishes, are very durable. 

 A peculiarity, in addition to the markings above noted, is the non- 

 porous character. The pores that are ever3'where present in the skins 

 of most mammals, which give the natural grain in the tanned leather, 

 are entirely indiscernible in the skins of these fish. The result is to 

 render them almost proof against water absorption. Although by 

 skillful tanning the fibers of seal and other skins may be plumped and 

 the liod}' of the memljrane solidified, ^et much water exposure loosens 

 up the fiber and gradually permits absorption. Not being of a porous 

 nature, shark skin is naturally free from this defect. But the advan- 

 tage is also a disadvantage in some respects. The nonporous leather 

 is practicall}^ airproof as well as waterproof, and that is a serious 

 defect when its use for footwear is considered. Beyond this, the 

 skins of sharks and similar fishes may be prepared in a very durable, 

 noncracking leather, for which many uses ma}^ be found. 



Formerly, large quantities of these skins were used for polishing 

 wood, ivory, etc., for which they are excellent, owing to their rough- 

 ness, hardness, and durability. But the great improvements made in 

 preparing emer}- compositions and sandpapers have resulted in sub- 

 stituting them almost entirel}' for polishing purposes. However, a 

 small demand yet exists for shark skins for cabinet-workers' use. 



The principal uses made of the skins of sharks and allied fishes at the 

 present time are for covering jewel boxes, desk ornaments, cardcases, 

 sword sheaths, sword grips, and a great variety of small articles for 

 which the tuberculous markings peculiar!}^ adapt them. The demand 

 for these purposes, however, is small and restricted, and each producer 

 has to develop his own market. Comparativel}^ few of these skins are 

 prepared in the United States, and diligent search among the tanneries 

 and leather stores will result in the finding of only a few skins. Many, 

 however, are prepared in France, Turkey, and other countries of 

 southern Europe, and also in China and Japan. 



A Parisian manufacturer has made quite a reputation tanning the 

 skin of a species of Malabar shark into morocco, and establishments 

 in Turkey make green leather from the skin of the angel shark found 

 in the Mediterranean Sea. The skin of the diamond shark obtained in 

 the North Sea, and so called because of the shape of the markings or 

 protuberances, is used to cover the sword grips of German ofiicers, 



