VEGETABLE KINGDOM. 133 



spicula sticking out from the sides of the fibres. Some of the siliceous 

 spicula are shown enlarged in Figs. 187 a-h. Many deep-sea species 

 consist mainly of siliceous fibres. They look as if made of spun glass 

 worked together into forms of great delicacy 

 and beauty. The annexed figure represents, 

 much enlarged, a species of sponge — a jelly- 

 like globule of minute size — which some- 

 times beclouds the sea in the Pacific. (It is 

 from the East Indian seas, and is named 

 Sphcerozoum orientale D.) It is bristled 

 with spicula. The death and decay of such 

 sponges would add largely to the silica of the 

 sea bottom. 



Some sponges secrete calcareous spicula instead of siliceous ; and 

 there are others that are chiefly calcareous in their constitution, and 

 consequently look like masses of a compact coral. The large corals 

 referred to the genus Stromatopora, and others allied, are regarded by 

 some zoologists as either calcareous sponges or foraminifers. 



3. VEGETABLE KINGDOM. 



The vegetable kingdom is not divisible into sub-kingdoms like the 

 animal ; for the species all belong to one grand type, the Radiate, the 

 one which is the lowest of those in the animal kingdom. The follow- 

 ing arc the higher subdivisions. 



I. Cryptogams. — Having no distinct flowers or proper fruit, the 

 so-called seed being only a spore, that is, a simple cellule without the 

 store of nutriment (albumen and starch) around it which makes up a 

 true seed ; as the Ferns, Sea-weed. They include — 



1. Thallogens. — Consisting wholly of cellular tissue ; growing 

 mostly in fronds without stems, and in other spreading forms ; as (1) 

 Algae, or Sea-weeds; (2) Lichens; (3) Fungi, or Mushrooms. 



2. Anogens. — Consisting wholly of cellular tissue ; growing up in 

 short, leafy stems ; as (1) Musci, or Mosses ; (2) Liverworts. 



3. Acrogens. — Consisting of vascular tissue in part, and growing 

 upward; as (1) Ferns; (2) Lycopods (Ground-Pine); (3) Equiseta; 

 and including many genera of trees of the Coal period. 



II. Phenogams. — Having (as the name implies) distinct flowers 

 and seed ; as the Pine, Maple, and all our shade and fruit trees, and 

 the plants of our gardens. They are divided into — 



1. Gymnosperms. — Exogens, or Exogenous in growth : that is, the 

 plant has a bark, and grows by an addition annually to the exterior of the 

 wood, between the wood and the bark, and hence the wood shows in a 

 transverse section rings of growth, each the formation of a single year 



