18 BRITISH FRESHWATER HEL1OZOA. 



Wallich (1863) records an 'individual found at 

 Hampstead, London, 500 /x, in diameter, spherical in 

 shape and resting attached by the extremities of its 

 pseudopodia to the sides of a glass vessel. 



The nuclei have a tendency to increase in size as 

 the individual grows ; in a specimen from Hampshire 

 measuring 550 /x, in diameter many of the nuclei were 

 25 fj. in diameter, but as it was observed under a cover- 



FIG. 181. Actinosph^i-iniii eichhornii. A small animal captured by 

 the pseudopodia is seen at m. in process of ingestiou. Other 

 organisms are enclosed in food-vacuoles in the endoplasm. c.v. 

 Contractile vesicles. The figure on the right shows the depression 

 left on the collapse of a contractile vesicle. (After Wallich.) 



glass its normal spherical diameter might have been 

 less than this. 



The number of nuclei varies greatly, but increases 

 with the size of the individual ; the numbers visible in 

 a living specimen, however, are many fewer than 

 those that may be recognised if it be stained and com- 

 pressed under a cover-glass, by which means from one 

 to three hundred nuclei may be found, according to 

 the size of the specimen. 



