HARDWICKE'S SCIENCE-GOSSIP. 



8i 



being instructed as to patterns, &c., but then, of 

 course, he (the reader) would lose all the honour and 

 glory of having made them himself. The best fossil 

 fish teeth to mount, are those from the Red Crag, 

 on account of their rich colours. They may readily 

 he obtained at Ipswich. 



P. Tracy. 

 Ipswich. 



of single cells. The basal cell is club-shaped towards 

 the apex of the plant, gradually getting narrower and 

 narrower, before it widens out into the branched 

 attachment disc. The apical cell is frequently 

 elongated into a long trichome structure (Fig. 72 : i). 

 The cells are filled with spindle-shaped chlorophyll 

 grains, and the nucleus (with nucleolus) is occasionally 

 quite clearly visible without staining (Fig. 72 : 3). 



Fig. 72. — (i.) Young plant with hair at apex. (2.) Oidogonium showing annular cushion at a, which has actually been drawn 

 out at b. (3.) CEdogoniiim cell. (4.) Formation of androgonia at b, and result of intercalary growth at a. (5 and 6.) Escape 

 and germination of zoogonidium. (7.) Fertilised oosphcre (= oospore). (8.) Androgonia settling. (9.) Three dwarf males on 

 an oogonium. (10.) Dwarf males germinating on cells below the oogonia. (11.) The act of fertilisation. The anthrozoa is 

 just vanishing as a black spot into the substance of the oosphere. (12.) Mature oospore. 



NOTES ON CEDOGONIUM. 



ONE of the commonest and prettiest green fresh- 

 water algae is CEdogonium ; it is found growing 

 on the submerged parts of water-plants, and on other 

 solid bodies ; it is not branched, but consists of a row 



The filaments grow by intercalary growth ; a kind 

 of annular cushion, consisting of cellulose, is formed 

 at one end of the cell. The cell wall ruptures cir- 

 cularly, and the cushion stretches over the gap ; this 

 rupturing is repeated for several times, thus, the end 

 of the cell, which had the cushion, looks as if it con- 



