XXXVI INTRODUCTION.' 



There is something singular in the strict locality 

 of shells : one would hardly imagine that particular 

 species, capable of locomotion, had distinct places 

 of abode, from which they never swerve, unless forced 

 by accident. They are also affected by difference of 

 temperature. When Pero'n visited New Holland, he 

 found, at its southern extremity, the great sea-ear, 

 Haliotis gigantea, in full perfection. It is there 

 found in large quantities, and is of essential service 

 to the inhabitants of Van Dieman's Land, who 

 derive from its flesh an abundant and wholesome 

 nourishment. Upon moving but a short distance 

 towards a warmer latitude, he found the shell de- 

 crease in size ; and, in proportion as he proceeded, 

 it became less and less, till, at the port of Rio 

 Georges, it totally disappeared. This happened to 

 other species as well as the sea-ear, whence it 

 may be inferred, that the animal inhabitants of 

 shells, originally of cold climates, cannot exist in 

 the torrid zone. The contrary will also hold with 

 respect to those of hot climates, and upon this 

 position Peron has the following remarks : 



Of all the countries which we have hitherto seen, 

 there is not one to be compared to Timor, for the 

 abundance and variety of its shells. The richness 

 of its shore, in this particular, is really beyond all 

 expression. We have collected from it more than 

 twenty thousand shells, among which may be dis- 

 tinguished many hundred species ; and yet, of this 



