•4 PALAEONTOLOGY 



simple forms, and embraces chiefly the remains of the animal 

 kingdom. 



A reference to the subjoined "Table of Strata" (fig. 1) will 

 indicate the relative position of the geological formations 

 cited. The numerals opposite the right hand give the approxi- 

 mative depth or vertical thickness of the strata. 



Organisms, or living things, are those which possess such 

 an internal cellular or cellulo-vascular structure as can receive 

 fluid matter from without, alter its nature, and add it to the 

 alterative structure. Such fluid matter is called "nutritive,'' 

 and the actions which make it so are called "assimilation" 

 and " intus-susception." These actions are classed as "vital," 

 because, as long as they are continued, the "organism" is said 

 " to live." 



When the organism can also move, when it receives the 

 nutritive matter by a mouth, inhales oxygen and exhales 

 carbonic acid, and developes tissues the proximate principles 

 of which are quaternary compounds of carbon, hydrogen, 

 ( .xygen, and nitrogen, it is called an " animal." "When the 

 organism is rooted, has neither mouth nor stomach, exhales 

 oxygen, and has tissues composed of "cellulose" or of binary 

 or ternary compounds, it is called a " plant." But the two 

 divisions of organisms called "plants" and "animals" are 

 specialized members of the great natural group of living 

 things; and there are numerous beings, mostly of minute 

 size and retaining the form of nucleated cells, which manifest 

 the common organic characters, but without the distinctive 

 superadditions of true plants or animals. Such organisms are 

 called " Protozoa," and include the sponges or Amorphozoa, the 

 Foraminifera or Bhizopods, the Polycystinece, the Diatomacece, 

 Desmidice, Ghregarinoe, and most of the so-called Polygastria of 

 Ehrenbers, or infusorial animalcules of older authors. 



