INTRODUCTION. 



THIS little book differs in several notable particulars from most 

 of those of the " Young Collector " series that have already 

 appeared. First, the creatures herein described are living pets, 

 the occupants of the Vivarium and not the Cabinet. Next they 

 are few ; the intention of these volumes being to treat of British 

 species only, and Britain has but few reptiles. Thirdly, though 

 still comparatively small creatures, they belong to the important 

 group of Vertebrata or back-boned animals. 



Those of our young collectors who have already possessed 

 themselves of Kirby's, Butler's, Woodward's, and Skuse's contri- 

 butions to this series, will have observed that the Insects, Shell- 

 fish, and Crustaceans treated of are boneless ; and that, compared 

 with the rest of the animal kingdom, all are very small creatures. 

 It is worthy of note that out of the seven sub-kingdoms in which 

 zoologists have generally arranged the inhabitants of the globe, 

 six are composed entirely of these small, boneless creatures, while 

 the one remaining sub-kingdom, animals with a bony skeleton, 

 the Vertebrata^ embraces the largest and the most important 

 groups, including man. Persons who have acquired the habit 

 of observing nature those particularly who incline to the study 

 of animated nature cannot fail to be impressed by its teeming 

 life in myriad forms. Even in a city during the summer, birds 

 and insects are abundant ; and we have only to place some pond 

 weed in a glass bowl of water, and a world of life will soon inhabit 

 it. Should our home be in rural districts, and our inclination 

 lead us to study the denizens of trees, streams, or meadows, we' 

 become fairly puzzled as to which class of beings to choose and 

 where to begin. Within a square foot of soil on the bank where 

 we rest we may, with an ordinary magnifier, see more living 



