LIFE ON THE EARTH. 



27 



These may be again subdivided so as to make four 

 great groups : viz. 



X 



1. Dicotyledones. Embryo 

 with two seed-lobes, stem 

 growth outward, leaves reticu- 

 lated, symmetry quinary or 

 quaternary (as Ranunculacece, 

 Rosacece, Labiatce, Coniferce). 



2. Monocotyledones. Em- 

 bryo with one seed-lobe, stem 

 growth internal, leaves usually 

 with parallel veins, symmetry 

 ternary (as Liliacece, Aracece, 

 Gramineoe). 



Phanerogamous plants 

 with stamens and pistils, 

 spiral vessels, and seeds. 



Cryptogamous plants, 

 without flowers, true sta- 

 mens, pistils, spiral vessels, 

 or seeds. 



3. Acrogens. Stem, with 

 leaves and branches, mostly 

 traversed by vessels (as Filices, 

 Lycopodiacece, Equisetacem). 



4. Thallogens. No distinct 

 stem or leaves, or vessels, but 

 cellular expansions (as Liche- 

 nes, Algce, Fungi). 



In like manner Animals may be collected in four 

 great groups : 



I. Yertebrata. Brain protected by bony (or cartilaginous) 



case, and, proceeding from it, a nervous trunk car- 

 ried along the upper side of a chain of articulated 

 bones (vertebrae) or a corresponding cartilaginous 

 axis. Symmetry bilateral. 



II. Articulata. Body jointed or ringed across. A double 



