•VOL. XtlV.J PHILOSOPHICAL TRANSACTIONS. 335 



The Figure of the Mustela Fossilis. Communicated from Dr. Gronovius at 



Leyden. N° 483, p. 45 1 . 

 Mustela fossilis, sive cobites coerulescens, lineis quinque nigris longitudinali- 

 bus. Arted. Ichthyol. gen. xi. 3.* See fig. 1, pi. 8. 



This fish was kept alive in a jar of water a year wanting Q days, without chang- 

 ing the water, and without any other food than what the water afforded. These 

 fish are dug out of the sands near Wesel in Holland. 



On the Belluga-Stone. By Mr. Peter Collinson, F.R.S. N°483, p. 451. 



These stones of the belluga -^ were collected by Dr. Cook at Astracan. The 

 calculus of the belluga is found of various shapes and sizes ; it is mostly of a 

 flatted oval figure, sometimes roundish, globular with unequal depressions, and 

 of a yellowish white colour externally, and a smooth polished surface. It differs 

 in magnitude, as it does in figure, fi-om the bulk of a pigeon's egg up to 4 or 5 

 times that size. 



They are mostly compact, ponderous and solid, not very friable, but requiring 

 a pretty smart blow of a hammer to break them. They yield easily to the saw ; 

 but this defaces their internal texture, which is very remarkably elegant and re- 

 gular. The stones consist of concentric coats firmly adhering to each other, 

 formed about a nucleus, which appeared to be quite a heterogeneous substance, 

 from its colour, hardness, and texture. 



But another obvious circumstance in its structure renders the belluga stone dif- 

 ferent fi-om most others, which is its radiated appearance. It seems composed 

 of an infinite number of shining rays, regularly diverging from the central nu- 

 cleus to the circumference, representing both in colour and form the flakes of a 

 pure white terra foliata tartari, or (excepting the colour, which is yellowish) the 

 striated spicula of antimony. 



This stone is found in the fish called the belluga, a species of sturgeon, the 

 acipenser tuberculis carens artedii, part iii. p. Q2. It is commonly called lapis 

 bellugae, by the Russians kamen belluga, which signifies the same thing. 



Of this fish several authors have given the following account. In shape it is 

 not much unlike a sturgeon, | only its snout is proportionably shorter and thicker; 

 the skin on the back is light grey, but under the belly it is white, and without 



* Willoughbyj Hist. Pise. p. 124, tab. G. 3,4. Raii Syn. Pise. p. 09. — Orig. Cobitis fossilis, Linn. 



+ The fish in which the eoncretion here desciibed is found, is the acipenser huso of Linn, or 

 isinglass sturgeon, sometimes called beluga or belluga. The stone, according to Dr. Pallas, is found 

 in the kidneys of the fish. 



The beluga here mentioned must by no means be confounded with another animal of the tame 

 name, which belongs to the whale tribe, and is the delphinus leucas, Linn. Gmel. 



J Vide Crull's History of Russia.— Orig. 



