14 PEOTOZOA. 



be made either to coalesce into larger or be divided into smaller cavities 

 presenting in all respects the character of the normal ones. 



The filamentary appendages to the periphery of this animalcule are 

 essentially tentacular organs, composed of the same substance as the 

 rest of the body, from which they differ only in never having vacuoles 

 in their interior ; and if granules are to be detected in their structure, 

 these are very few in number. 



(29.) The mode in which the Actinophrys is nourished is a subject 

 of the highest interest. Although, as has been stated, the creature has 

 neither mouth nor stomach, yet it lives upon solid nutriment and re- 

 jects such parts as are indigestible. The Actinophrys, indeed, feeds 

 upon Infusoria of all kinds, on the lower Algse, such as the Diatomaceae, 

 and even on minute Crustacea, as the young of Lynceus, Cyclops, &c., 

 which it accomplishes in the following manner : When, in its progress 

 through the water, it comes in contact with fitting food, the object, 

 whether of animal or vegetable nature, as soon as touched by one of the 

 tentacular filaments, usually becomes adherent thereunto. The fila- 

 ment, with prey thus attached, then slowly shortens itself, dragging 

 the object seized towards its devourer, all the surrounding filaments 

 bending their points together, so that the captive becomes at last en- 

 closed on every side (fig. 5, 2, /). 



(30.) That the tentacles, however, possess some other power than that 

 of mere prehension appears evident, because nearly every creature of 

 moderate and even immoderate size which strikes against them is at once 

 for a time rendered immoveable. When a Rotifer, in crossing the field 

 with velocity, strikes against any object, the rotatory organ is often seen 

 at once to suspend its operation, more particularly should its cilia strike 

 the cilia of another animalcule; and frequently no notice whatever is taken 

 of the shock ; not so, however, with the victim of the Actinophrys Sol, on 

 the instant of contact with whose tentacles it appears to be paralysed. 



In some cases the prisoner is held for some seconds on the exact 

 spot where it struck, and then, without any visible means, becomes 

 attracted towards the body of the Actinophrys, gliding slowly down the 

 tentacle until it is jammed between its base and a neighbouring one. 

 In other instances, instead of the prisoner being arrested on or near 

 the extremity of the tentacle on which it strikes, it is shot down to the 

 base with extreme rapidity, to occupy the same position as in the former 

 case. Sometimes it would seem as if the appetite of the Actinophrys 

 were sated, or that the captive was not approved of, for after remain- 

 ing stunned for a few seconds, ciliary action is feebly recommenced, not 

 sufficient to produce motion, but as if a return to vitality had been 

 effected ; shortly it is seen to glide off the tentacle (as if that organ 

 possessed the power both of appropriation and rejection), and fre- 

 quently, with but little sign of recovered life, it floats out of the field. 



(31 .) But should the Actinophrys be hungry, the spot upon which 



