150 



LOWER VERTEBRATES. 



recorded of its habits, and few specimens exist in museums. Species of Stenodus are 

 said to inhabit the Volga, Obi, Lena, and other northern rivers, but as yet little definite 

 is known of them. 



The grayling ( Thymallus) termed by St. Ambrose " the flower of fishes," is like- 

 wise intermediate between the white-fish and the trout, having larger scales than the 

 latter, and feebler teeth. The teeth on the tongue, found in all the trout and salmon, 

 are in the grayling obsolete. The chief distinctive peculiarity of the genus Thymallus 

 is the great development of the dorsal fin, which has more rays (20 to 24) than in 

 any other of the Salmonidee, and the fin is also higher. All the species are gayly 

 colored, the dorsal fin especially being marked with purplish or greenish bands, and 



FrG. 97. — Thymallus thymallus, grayling, and Satvelinus alpinus, red cliarr. 



bright rose-colored spots ; while the body is mostly purplish-gray, often with black 

 spots. Most of the species rarely exceed a foot in length, but northward they grow 

 larger. Grayling weighing five pounds have been taken in England, and according to 

 Dr. Day, they are said, in Lapland, to reach a weight of eight or nine pounds. 



The grayling, in all countries, frequents clear, cold brooks, and rarely, if ever, 

 enters the sea or even the larger lakes. They are said to congregate in small shoals . 

 in the streams, and to prefer those which have a succession of pools and shallows, 

 with a sandy or gravelly, rather than a rocky bottom. It spawns on the shallows in 

 April or May (in England), and is said to be non-migratory in its habits, depositing its 

 ova in the neighborhood of its usual haunts. The ova are said to be far more delicate 

 and easily killed than those of the trout or charr. 



