Production of Isinglass on the Coasts of India. 83 



of cartilaginous fishes, which are so named from the skeletons being 

 devoid of bony fibres, and chiefly composed of cartilage, with the lit- 

 tle calcareous matter deposited in small grains. Among these along 

 with the Sturgeons, are arranged the Shark, Ray, and Skate, as well 

 as the Lamprey and the Myxine, the most imperfect of fishes, and 

 indeed of vertebral animals. 



The Sturgeons are easily distinguished by having bony bucklers 

 implanted in longitudinal rows on their skin, and by having their 

 heads, to use Cuvier's expression, similarly cuirassed. The mouth is 

 small, devoid of teeth, and placed under the muzzle. They resemble 

 ordinary fish by having their gills free, which have but a single 

 orifice, and by being oviparous. Internally, they are characterised 

 by having a large swimming bladder, which communicates by a wide 

 hole with the oesophagus. They ascend several rivers in great 

 numbers from different seas, and thus give rise to very profitable 

 fisheries, as their flesh is in some countries esteemed as food, both in 

 a fresh and salted state, while their eggs form Caviare, and their 

 sounds Isinglass. 



As the genus Acipenser is known to consist of several species, it 

 might be expected that Isinglass is yielded by more than one of them. 

 This is found to be the case with several, though all the species of 

 the genus have not yet been accurately determined. A few have 

 been known from early times ; several were determined by Pallas, no 

 less than nine are figured and described in the Medical Zoology of 

 Brandt and Ratzeburg.* 



* Medizinische Zoologie von J. F. Brandt und J. T. C. Ratzeburg. Ber- 

 lin, 1829. 



The following are the species which are best known, in consequence of their be- 

 ing caught and valued for their products:— 



The Common Sturgeon (Acipenser Sturio) — Br. and K. tab. iii. fig. 1, — which 

 is usually about six or seven feet in length, and is found in the Atlantic Ocean, on 

 the coasts of France and of England, in the North Sea, Baltic, and German 

 Ocean, whence it ascends the rivers of France and Germany. It is occasionally 

 caught in the Thames, and used formerly to be considered a royal fish, and much 

 prized, probably on account of its rarity. The flesh, somewhat resembling veal is 

 eaten both in a fresh and salted state. The roes yield an excellent Caviare, the 

 swimming-bladders may yield Isinglass, but are not applied to any use, probably 

 because too few are obtained at a time. 



