172 INTRODUCTION TO ZOOLOGY. 



season, not less than forty tons. This must, however, be 

 greater than the average of ordinary seasons, when causes 

 connected with the scarcity or high price of provisions, which 

 then prevailed, are not in operation. But after every such 

 allowance has been made, the quantity used as food is very 

 considerable. This is attested in other localities round the 

 coast, by the large heaps of shells which may be seen about 

 the dwellings of the humbler classes. 



The entrance to the Bay of Belfast, and the loughs of 

 Strangford and Garlingford, furnish a valuable supply of oysters, 

 which are conveyed for sale to considerable distances. The 

 Garrickfergus oysters are large in size, and so much in demand, 

 that their price in the Belfast market is generally from twelve 

 to fifteen shillings per hundred of 120 oysters. It is occa- 

 sionally 20s. ; and we have known one instance in which so 

 much as 30s. was paid. The price of the pearl oysters,* 

 when landed on the beach at Condatchy, varies from 14s. to 

 6 per thousand; so that the best edible oysters are sold 

 in these countries at more than the pearl oysters at Ceylon. 



It is interesting to the botanist, in passing over moor, and 

 mountain, and valley, to observe the kind of plants which are 

 found in each of these situations, and which could not thrive, 

 or perhaps could not live, if removed to any of the others. 

 A similar pleasure awaits the zoologist, who, in his progress 

 round the coast, notes how the species of marine animals 

 which are abundant in one district have disappeared as the 

 coast changes its character, and have their place supplied by 

 species altogether different, but suited to the nature of the 

 locality where they are found. Thus the coast, both to the 

 north and to the south of Belfast Bay, is rocky, and Limpets 

 are, accordingly, plentiful. Within the bay, and opposite to 

 the village of Holy wood, t are extensive mud banks, which, 



* Steuart on the Pearl Fisheries at Ceylon. 



f An old inhabitant of that village has favoured us with the following 

 particulars : 



"The year 1792 or 1793 was remarkable for the great drought that 

 prevailed, and the distress consequent upon it. In the month of June 

 or July, that year, about twenty families of poor people came from the 

 interior of the country, and encamped along the road side and on the 

 beach, a short way to the west of Holywood. They remained there 

 about live weeks, during which they subsisted partly on such vegetable 

 food as they were able to pick up about the hedge-rows and fences, but 

 principally upon the mussels which are so abundant on ' the bank,' about 



