64 FEESH- WATER EHIZOPODS OF NORTH AMERICA. 



dopodal lobes, and were provided with a terminal villous process of varia- 

 ble form, They glided along with the body straight and slightly sinuous, 

 or often curving to one side or the other. Frequently they presented little 

 change of form, the head alone incessantly rolling forward concurrent with 

 contraction of the body behind; but often they projected pseudopodal lobes 

 on each side nearly or quite as thick as the head end itself. Though 

 habitually of the shape described, these little Amoebae Avould at times 

 assume a variety of forms. When at rest, they were more or less depressed 

 globular or oval. 



The villous process terminating the body had the appearance of a 

 protniding portion of the endosarc. It was often observed with adherent 

 algae, fig. 4, dragged about in the movements of the animal. 



The ectosarc was always thickest at the head end, or in advance of the 

 pseudopodal lobes, and thinned away to nothing at the villous process. 



The endosarc was composed of the usual pale granular matter, with 

 variable proportions of coarser granules and sometimes small clear globules. 

 Distinct crystals, likewise in variable proportions, and some of them 

 comparatively large, -were always present. A large contractile vesicle was 

 another conspicuous constituent, and occasionally a Second occurred. The 

 nucleus was globular, homogeneous, and faintly granular, and was defined 

 by a thin halo. 



The Amoebae commonly contained as food a number of the green algae 

 among which they lived. Frequently some of these algae within the endo- 

 sarc had become bright reddish brown as a result of digestion. 



Occasionally individuals were observed to assume a globular shape, 

 and then spread out and remain quiescent, as seen in fig. 11. In this con- 

 dition, the body was undefined by any trace of clear ectosarc at the border, 

 and the contents were rendered unusually distinct. The contractile vesicle 

 remained unchanged 



Among these Amoeba3, I observed several of especial interest. While 

 having the same general features as the others, they contained from one 

 to half a dozen large nuclei, which were coarsely and uniformly granular, 

 as seen in figs. 12-16. When these were in greatest number, together 

 with the pulsating vesicle, which approximated them in size, they occupied 

 the greater part of the body of the animal. In its movements, both the 

 nuclei and the pulsating vesicle would at times exhibit the effects of mutual 



