'ri INTRODUCTION. 



the shackled routine of their ordinary scientific 

 descriptions. 



Next, they may be obtained by a very small 

 amount of labour and research : there are few rock- 

 tracks between the tide -levels which will not afford 

 a harvest to an explorer of ordinary observation. 



Further, they may be kept in the drawing-room 

 or the study without trouble or annoyance, and may 

 be carried away to our country-houses as a per- 

 manent memorial of our visit to the sea-side. 



So, too, they form an excellent means of intro- 

 duction to the study of Natural Histor3^ Few 

 people have either the time or the inclination to 

 enter upon the vast field of the animal and vegetable 

 kingdoms, with the intention of mastering either 

 subject as a whole. Few people, for instance, could 

 be induced to attack a book like Carpenter's * Prin- 

 ciples of Physiology,' in which the general laws of 

 the subject are scientifically detailed. But very 

 many persuade themselves to invest a little spare 

 money in a Handbook of Ferns, or a popular treatise 

 on Butterflies, and after a time discover to their 

 delight that a small expenditure of time and obser- 

 vation has enabled them to become familiar with 

 one branch of the great subject. Thus they are 

 led on insensibly to become Natural-History stu- 

 dents, and find at length that they have made no 

 small progress in the journey which they feared to 

 commence. 



