ON PELOMYXA VIEIDIS. 373 



substance in these large Pelomyxfe forms a considerable mass, 

 and this breaks up very readily after death into small 

 droplets. 



I find nothing in the structure of P. viridis which would 

 lead one to suppose that these organisms have any affinities, 

 other than those usually assigned to them. Pelomyxa 

 belongs, as Biitschli says, to the family Amoebsea lobosa. 



In spite of repeated endeavours I am unable to throw any 

 light upon the reproductive processes which may obtain in 

 Pelomyxa. 



EXPLANATION OF PLATE XXVITI, 



Illustrating Professor Alfred Gibbs Bourne's paper on 

 "Pelomyxa viridis." 



Fig. 1. — An entire specimen, partially spread out under a cover-glass, 

 magnified about four diameters. In the left-hand lower corner is a Daplinia 

 shell, which the animal had just extruded. The opacity of the central region 

 is caused by a great accumulation of mud or sand particles. 



Fig. 2. — Extremity of a blunt pseudopodium, which is retreating. Small 

 droplets of the colourless non-granular protoplasm are being left sticking to 

 the slide ; some of these will become detached as the pseudopodium retreats 

 further. The magnification is not sufficient to allow of the nuclei and vesicles 

 being distinguished, but a few of the larger vacuoles, v, v., are seen. 



Fig. 3. — A long thin pseudopodium in the act of retreating, drawn to an 

 even smaller scale than the preceding figure. 



Fig. 4. — Extremity of a blunt pseudopodium, more highly magnified. The 

 existence of the peripheral layer of colourless protoplasm indicates that the 

 pseudopodium is not being actively protruded, while its small extent and 

 comparative regularity shows that the pseudopodium is not being rapidly 

 withdrawn, n. n. Nuclei, f. v. Food vacuole, containing food debris, s. 

 Naid seta. m.m. Sand or mud particles, v. v. Vacuoles. The small circles 

 which are shown all over the figure, except in the colourless peripheral portion, 

 represent the vesicles with their chiorophyllogeuous contents. In places 



