4 FRESH- WATER RHIZOPODS OF NORTH AMERICA. 



Some of my most delightful recollections are associated with expe- 

 ditions into the Uinta Mountains conducted by Judge W. A. Carter, of 

 Ft. Bridger, or his son-in-law Dr. J. Van A. Carter. At an elevation of 

 from eight to ten thousand feet the mountains are covered with forests, 

 chiefly of Fir and Pine, with a most wonderful profusion of beautiful flow- 

 ering plants beneath. The forests here and there enclose bright, grassy 

 meadows and ponds, favorite resorts of deer, and in these I obtained rich 

 materials for my investigations. 



Whatever may be thought of the pertinence of publishing such works 

 as the present one with the Reports of the Geological Survey of the 

 Territories, to remove any misapprehension in the matter I deem it proper 

 to state that my contribution has been given without pecuniary recompense. 

 In my own judgment, Prof. Hayden has acted with the most enlightened 

 view in authorizing and encouraging such natural-history investigations 

 as woidd be facilitated by explorations of the country in which his 

 geological surveys were conducted. With the exception of the cost of 

 publishing the present Report, the only additional expense to which I put 

 the Survey during my explorations in the West amounted to about $222. 

 Much expense was saved through the liberality of various railroad compa- 

 nies in giving me the privilege of free travel and travel on half-fare. 



GENERAL REMARKS ON THE RHIZOPODS. 



The simplest kinds of Rhizopods are unprovided with a protection or 

 support of hard parts of any kind, possessing, at least in their ordinary 

 active condition, neither a shell nor an investing membrane. In all kinds, 

 the soft substance of the animal mainly consists of a fluent, viscid, albumi- 

 noid jelly, endowed with an extensile and a contractile power, by which the 

 creature is enabled to execute all those movements which ordinarily distin- 

 guish animal life. 



The motile jelly of the Rhizopod is regarded to be of the nature of the 

 common elementary basis of organic bodies in general, and, like it, is called 

 the protoplasm (Gr. protos, first ; plasso, I mould : — the primitive material 

 from which organic bodies are moulded). Its resemblance in motive power 

 to muscular tissue, or the flesh of more complex animals, led the French 

 naturalist Dujardin, who was the first to indicate the true nature of the 

 Rhizopods, to give it the name of sarcode (Gr. sarx, flesh ; eidos, form). 



