BARNACLES. 



279 



Fig. 211. 



(Anseres arbor ei). Old Gerarde speaks most deci- 

 dedly of having witnessed the whole process of deve- 

 lopment ! The story is much older than his period, 

 and was told and illustrated by 

 Sebastian Munster, in his ' Cosmo- 

 graphia Universalis,' as long ago 

 as 1572. 



The sessile barnacles appear to 

 be more easily acclimatised in 

 aquaria than the stalked. The 

 latter are usually drifted about at 

 sea, and possibly miss this artificial 

 mode of aeration when confined in 

 a tank. 



The star-fishes, sea-urchins, and 

 marine worms, like the Crustacea, 

 are capital adjuncts to what we may 

 call the " still life " of an aquarium. 

 They fill up as detail, make a good 

 fore or background, and intensify 

 the interest always felt in seeing ob- 

 jects of which we have heard or read alive for the first 

 time. The star-fishes and sea-urchins are nearly re- 

 lated, in spite of their apparent unlikeness, both being 

 grouped into an order called Echinodermata, or " spiny 

 skinned." Both move by means of suckers, which 

 are worked by a wonderful hydraulic apparatus from 

 within the test or shell. In the sea-urchin the, shell is 

 made up of at least six hundred pieces, mosaicked 



Young Cirripede 

 (enlarged) immedi- 

 ately after moulting 

 the pupal carapace 

 and assuming its natu- 

 ral position, a. An- 

 tennae, c. Natatory 

 umnoulted legs. 



