LIFE HISTORY OF A FERN. 237 



The archegonium is a multicellular body, possessing a central 

 canal, terminating in a circular cavity containing the germ-cell, 

 from which, after fertilisation, will spring the future plant. 



The antheridium is a closed sac, within which are enclosed the 

 mother-cells of the antherozoids, and from which they are expelled 

 after arriving at maturity by the rupture of the outer cell-wall. 

 The antherozoids thus set free are minute bodies possessing the 

 power of locomotion by means of the rapid motion of the vibra- 

 tile cilia with which they are furnished ; and they are thus brought 

 into contact with and fertilise the germ-cell of the archegonium. 

 In these strange bodies we approach curiously near to some of the 

 lower forms of the Infusoria, and find ourselves in the mysterious 

 border-land where animal and vegetable commingle with scarcely 

 a perceptible dividing line. 



After fertilisation, the germ-cell undergoes further changes by 

 division and sub-division, the resultant cells becoming differen- 

 tiated, and each by independent vegetative processes developing 

 the various parts of the mature plant : root, stem, rachis, frond, 

 and spores. The young plant, when first formed, remains in con- 

 tact with the prothallium, from which it derives its principal 

 nourishment. After a time, however, the prothallium gradually 

 withers away, and the young Fern commences its independent 

 existence. 



Taking them in this order, we commence with the roots, which 

 are usually fine fibrous hairs, especially fitted for effecting an 

 entrance into and between the several interstices in the old walls, 

 rocky caverns, or stony hedge-banks, where so many of the Ferns 

 delight to luxuriate. 



The stems of Ferns are for the most part underground or 

 creeping upon the surface. Where they are ascending they do not 

 attain to any size in this country ; but in the Tree Ferns of tropi- 

 cal lands they grow to the dimensions of forest-trees. But whether 

 creeping or ascending they all partake of a similar character, and 

 consist internally of a central pith, outside of which is a loose 

 mass of cells enclosing a number of isolated vascular bundles, and 

 surrounded by a continuous network of vascular tissue with large 

 meshes, each mesh opposite to the point of insertion of one of the 

 leaves, the vascular bundles of each leaf being given off from the 



International Journal of Microscopy and Natural Science. 

 Third Series. Vol. VII. r 



