1330 THE STORY OF THE UNIVERSE 



thus classified with the jelly-fish are called Hydrozoa, 

 or Water Animals, and they pass two lives, one of 

 which is commonly observed on the seashore every- 

 where. One life is a fixed one, and the other is a 

 free swimming one; in one stage it is eating and 

 drinking, and in the other, these functions are not 

 always or often carried out. The egg-laying and 

 perpetuation of the animal are the duty of the greater 

 part of the beautiful branched and hair-like things 

 which are arranged by visitors to the seaside in pat- 

 terns, and retained as memorials of pleasant days, 

 and which are popularly called sea-weeds. They are 

 not such things, but are the delicate stems, branches, 

 and bud-like homes of the parents of tiny jelly-fish, 

 which are only to be caught in the open sea. These 

 horny stems and branches end in creatures with ten- 

 tacles or feelers, and they live between tides, in rock 

 pools, and at low water. 



Sometimes these fragile, plant-looking things are 

 fixed on to stones or sea-weed, and some get a ride by 

 growing on shells, inhabited, since the death of their 

 original possessor, by the Hermit Crab. 



One very numerous tribe of these feathery-looking 

 weeds, but which are truly animals, is common every- 

 where on the shore, between tide-marks into deep 

 water. Their stems are branching, and the little 

 bud-like things on them, when watched in still water, 

 may be seen to put forth pretty colored bodies with 

 tentacles around a centre; and as there may be hun- 

 dreds of them on the branches and stem, the crea- 

 ture resembles a bunch of rayed flowers. Hence the 

 name Sertularia, from sertula, a small garland. 



