40 THE COMMERCIAL SEA FISHES OF 



sea, where their presence would be naturally expected, had 

 they obtained entrance from the German Ocean. The exist- 

 ence of these fishes, in a comparatively leaner and smaller 

 condition in the Baltic than is perceived in their Arctic 

 relatives, renders it in the highest degree probable that 

 they are a remnant from the fauna of the Glacial Ocean. 

 During the later portion of the glacial period most of 

 Finland and the middle of Sweden were submerged, the 

 Baltic, which was a gulf of the Glacial Ocean, being closed to 

 the south. As the Scandinavian continent became elevated, 

 the Baltic became cut off by land from the Arctic, whereas 

 it has obtained an opening into the German Ocean, leaving 

 it containing representatives of its former glacial fauna, 

 but not the products of immigration through the Sound. 

 In 1825 Mr. Meynell, of Yarm, in Yorkshire, recorded how 

 he had succeeded in retaining smelts or sparling in a fresh- 

 water pond which did not communicate with the sea, and 

 how they not only bred, but throve there for successive 

 seasons. Mr. Arnold, of Guernsey, in 1831, observed upon 

 some experiments which he had personally undertaken in 

 a three-acre lake, having a muddy, gravelly, or rocky 

 bottom, and was principally filled with fresh water. Here 

 for nine months in the year, cattle came to drink, but in 

 summer the water was too salt, due to a supply from the 

 sea being received through a tunnel. Bass, grey mullet, 

 turbot, brill, plaice, soles, and smelt were introduced and 

 throve, while the mullet, it was remarked, bred as freely as 

 if they resided in the sea. After having been naturalised 

 in this lake, the fish were transferred to ponds of spring 

 water, where they not only lived, but did well. 



Salt-water piscinae have likewise been occasionally tried 

 with success along our coasts. In Kenmare Bay, Mr. 

 Bland, in an inlet guarded by reefs of rocks in Sneem 



