372 



THE MICROSCOrE. 



history of these minute parasites, are T7ell worthy of 

 investigation. 



The RliizoiJoda appear as creatures of a low type of 

 organization, and are considered, w^itli the former, to hohl 

 a medium state between animals and vegetables. Almost 

 all of them live in water ; it would be a fruitless search 

 to look for distinct internal organs, as the small bladder- 

 looking spaces enclosed within their substance, — believed 

 by Ehrenberg to be stomachs, — present only the appeai- 

 ance of transparent gelatinous cells, or rather moving^ 

 spaces, within the sarcodc envelope, and may be regarded 

 as the earliest dawn of a circulatory system. 



The term liliizopoda is derived from the Greek, and 



Fig. 205.— S/inj'Zc RkizopcnU. 



A, Di£ltigla proteiformis. b, Difflvgia ohJonga. c, d, Arcella acuminata nml 



dentaia. 



means " root-footed,"— the body is composed entirely of 

 gelatinous matter, sarcode, — motion being elfected by the 

 extension of portions of the substance into processes, 

 which, as in fig. 205, is seen to partake of various forms. 



Lobosa. — In the deposit formed at the bottom of fresli- 

 water ])onds, we may often meet with a singular minut*? 

 gelatinous body, which constantly changes its form even 

 under our eyes ; and moves about by means of finger-liko 

 processes, c^WfiApseudopodia, which it appears to have thd 

 power of shooting out from any part of its substance. 



