EDMONDSON — PROTOZOA OF IOWA. 1 5 



Difflugia acuminata is often found associated with Difflugia 

 pyriforniis in fresh water and is also in the ooze at the bottom of 

 lakes, ponds, etc. 



lycngth of the individual represented by Fig. 13, PI. II, 175 

 microns. 



Difflugia urceoi^ata Carter. 



Shell of large size, fundus usually evenly rounded, seldom 

 spined;neck short; mouth large, circular, surrounded by a reflected 

 rim with a thin edge; pseudopodia as in Difflugia pyrifomiis. 



Length, 250-300 microns. (Fig. 19, PI. III.) 



In size this is the largest species of the genus. Its distribution 

 over the state is, apparently, not very general, few localities hav- 

 ing furnished it. The best specimens have been obtained from 

 pond water in Muscatine county. Lake Okoboji, from which, in 

 August, 1905, were taken great quantities of other species of Dif- 

 JJugia, furnished none of Difflugia urceolata. 



Prof. Leidy reports a spined variety of this species from New 

 Jersey. None of the forms found in this state were spined. Fig. 

 19, PI. Ill, represents a variety of Difflugia tirccolata which is typ- 

 ical except for the possession of the posterior acuminate process 

 which, however, would hardly be considered a spine. 



Pseudopodia are of the common digitate variety, rarely being 

 branched. 



Difflugia lobostoma Leidy. 



Shell small, oval, usually composed of fine sand grains; mouth 

 terminal, small, with three or four well-marked lobes; pseudo- 

 podia as in other members of the genus. 



Length, 95 microns. (Figs. lo-ii, PI. II.) 



Figure 10, Plate II, illustrates a typical form of Difflugia lobos- 

 toma as it is usuallj' observed resting on the water. 



Figure 11, Plate II, is an oral view of an individual of the same 

 genus, showing the lobed nature of the mouth. The species is a 

 very common one in pond water and has a wide distribution, being 

 found in many localities in this state. 



Normally the organism rests upon its side, but by turning it so 

 that the mouth is visible it may easily be determined whether or 

 not it meets the requirements of this species. 



