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demon's part. He has a good deraoniaoal name— the black 

 goby — and a goad demoniacal nature. He lurka tinder the 

 roeks and weeds, -whence he will dart out with glaring eyes to 

 seize even one of his own cousine by the tail, and swallow him 

 alive." The stickleback had best mind himself when he 

 approaches the goby. 



The writer who draws such a graphic portrait of the goby 

 observes that many of the usual denizens of the aquarium dis- 

 play curious changes of colour ; even the little grey muUets, the 

 hardiest and most cheerful members of such a happy family, 

 change, when greatly alarmed, frooa iron-grey to a pale drab 

 colour. The little muUeta, who always like to live together, 

 dart about in shoals as lively as young ohiokens ; chase each 

 other after bits of bread or (sweetest of all to thrir palates) 

 prawns or shrimp spawn, and always keep up in a quart or 

 gallon or two of sea a pleasant bustle. 



Although not the most beautiful, it cannot be denied that 

 the vulgar periwinkle is one of the most useful members of 

 the aquaria— he is the scavenger — the snapper up of " trifles" 

 unconsidered by the careless tank-owner, but which if allowed 

 to accumulate unchecked would soon bring the entire establish- 

 ment to griet It should be understood that, if the miniature 

 ocean thrive, there will gather about the rock -works, and hang 

 like a thick green curtain upon the glass sides of the vessel, 

 a sturdy crop of bright green vegetation. The periwinkle is 

 the mower who reaps the green crop, and his tongue is his 

 scythe. " The watching of these mowers at work is one of the 

 prettiest sights the aquarium afibrds. It may be seen by the 

 naked eye, but the proprietor of a marine menagerie will find 

 it worth while to assist his observations with a pocket magni- 

 fying glass. Though his shell is not very handsome the peri- 

 winkle, with his zebra stripes and netted markings, is a fairly 

 pretty fellow when he comes out to eat the succulent young 

 growths of sea-weed on the sides of the aquarium. It is de- 

 lightful to. observe the working of the little scythe made by his 

 silky tongue, which is beset with rows of teeth that are them- 

 selves every tooth serrated. As the periwinkle eats, his fleshy 

 lips open, and his glistening tongue makes a rapid stroke, rasp- 

 ing the green surf with its teeth, and as it works on leaving 

 tiny marks exactly after the pattern of the marks left upon a 

 grass lawn by a mower." 



" The soldier crabs again, besides being worth careful study, 

 enliven the businesB of an aquarium with a great many 



