FISHES. 277 



with straiglit sides. Ordinary globes in which gold-fish are 

 kept distort the figure^ but through flat glass we get a side 

 view of their rich tints and very solemn countenances. 



Great advances in the science of ichthyology may be ex- 

 pected to take place as aquaria become common, but as yet 

 fishes have not formed a very prominent feature in them. 

 Very few salt-water fish have as yet been introduced, and 

 those belonging to fresh-water have to be assorted with 

 great care, to prevent mutual destruction. 



In this department therefore we must be content to 

 notice a few of the observations which have been made 

 upon some kinds confined in tanks. AYe begin with a fresh- 

 water species, which, from its habit of building a nest for 

 its young, is very interesting. 



Gasterosteus acui.eatus. 



The common Stickleback of our pools and brooks, so 

 well known to boys in every rural neighbourhood, may be 

 easily preserved, and if placed near the breeding season 

 with a few familiar water-plants growing in the tank, will 

 generally reward the possessor by an exhibition of its con- 

 structive powers. The following account is taken almost 

 entire from Mr. Hancock's communication, published in the 



