Vlll CONTENTS. 



III. 



HALF AN HOUR WITH SEA-WEEDS. 



How to collect sea-weeds. Abundance of species between 

 tides. The three groups of sea- weeds. Melanosperms, their 

 larger size. Boots of sea-weeds. The " Bladder- wrack." 

 Its air bladders. Fructification of sea-weeds. The Ser- 

 rated Wrack. The Knotted Wrack. The Small Wrack. 

 Laminaria. Halidrys. The Rhodosperms. Their deeper- 

 water habit. Beauty of many species. Polysiphonia. 

 Chlylocladia. Corallina officinalis. Capability of this and 

 other species to secrete lime. Delesseria. Ptilota, Griffith- 

 sia, Rhodymenia, Porphyra, Plocamium, &c. The "Pea- 

 cock " Laver. " Carrageen," or Irish Moss. The Chloro- 

 sperms. Enteromorpha, Ulva, Cladopliora, Bryopsis, &c. 

 How to mount sea-weeds. Necessity of marine vegetation 

 to marine life, &c Pages 34 to 50 



IV. 



HALF AN HOUR WITH SPONGES. 



Popular notion of a sponge. British sponges. CTialina 

 oculata. Its general structure. The three divisions of 

 sponges. Ornamental character of silicated sponges. The 

 " Glass Kope." Calcareous sponges. Their geological 

 antiquity. Ventriculites, &c. Keratose sponges. Structure 

 of Grantia. Halina, Leuconia, Microciona, Pachymatisma, 

 &c. The boring sponges. Their geological antiquity. 

 Halichondria species. General structure described. 

 Economic value of sponges. Their great importance in 

 geological operations. Their instrumentality in forming 

 flints, &c Pages 51 to 69 



V. 



HALF AN HOUR WITH SEA-WORMS. 



The study of natural history. False popular notions respect- 

 ing " imperfect " animals. The earth-worm and sea-worm. 



