140 



THE NATURE BOOK 



Serrated Wrack, and the Channelled 

 Wrack. The Bladder \\'rack has fronds 

 from one to three feet long, according 

 to the situation in which it is growing, 

 the bladders are in pairs, and the fruit 

 pods (receptacles) also grow in pairs at 

 the ends of the fronds, and are often 

 heart-shaped. The Knobbed Wrack has 



SEAWEED PARTIALLY COVERED WITH A G 

 (A colony of Moss-animal 



not quite such broad fronds but much 

 larger bladders ; indeed, the fisher lads 

 sometimes dry them and fashion them 

 into whistles. The Serrated Wrack has 

 no bladders, but the edges of the fronds 

 are toothed or serrated. The fronds of 

 this Wrack are frequently partly covered 

 with a delicate whitish tracery, each tiny 

 mesh representing what was once the 

 home of a very beautiful and interesting 

 little creature called a " Moss-animal," 

 or Bryozoon. The Channelled Wrack 

 grows chiefly near high-water mark, 

 seldom below half tide, for it seems to 

 require exposure to the air for many 

 hours every day. Growing in thick tufts 

 from three to six inches in length, desti- 

 tute of air bladders, and with a furrow in 

 its stem, it is easily recognised. 



Although the seaweeds are so numerous 

 and such familiar objects of the sea-shore, 



yet very few of them have popular names. 

 It is, therefore, practically impossible 

 to write about them without giving them 

 their scientific names, for the scientist 

 has been more eager to examine minutely, 

 and name, each individual weed than 

 has his lay brother. As we stand on the 

 edge of a breakwater, and look down 



into the water, 

 we shall see 

 that some of 

 the wooden 

 piles have a 

 \v o n d e r f u 1 

 growth of 

 beautiful green 

 tubular -shaped 

 weeds upon 

 them. This is 

 known as the 

 Enterornorpha 

 in ( e stin a lis, 

 which really 

 means " in the 

 form of an in- 

 testine," and 

 the weed varies 

 in length and 

 breadth from 

 short, narrow 

 fronds, to tubu- 

 lar ribbons 

 quite two feet 

 long. But it 

 is in the rock 

 pools that we see the seaweeds in all 

 their glory, and according to the situation 

 of each pool on the shore, so we shall 

 find it to contain certain species of sea- 

 weeds. In the pools nearest high-water 

 mark, we shall find the Wracks pre- 

 dominating, with the Enterornorpha, and 

 a delicate, soft, green growth called 

 Coifervci, and a deep green weed which 

 the fishermen call " Oyster-green." 



In the pools at about half-tide mark, 

 we shall find many beautiful and delicate 

 weeds, with dainty, thread-like, many- 

 branched filaments. One of these, to be 

 found in all tidal pools, is the Red Cera- 

 mium, which in its finest condition is a 

 delicate rosy red, its iilaments forked at 

 the ends with the joints more or less 

 transparent. The beautiful violet Poly- 

 siphonia is another denizen of the half- 

 tide pools, growing from about six to 



ROWTH OF BRYOZOA 



s.) 



