WHAT IS EOZOON ? 61 



body is capable of protrusion in any direction into long 

 processes, which are very mobile, and used for locomo- 

 tion and prehension. Further, this creature, though 

 destitute of most of the parts which we are accustomed 

 to regard as proper to animals, seems to exercise voli- 

 tion, and to show the same appetites and passions with 

 animals of higher type. I have watched one of these 

 animalcules endeavouring to swallow a one-celled plant 

 as long as its own body ; evidently hungry and eager to 

 devour the tempting morsel, it stretched itself to its 

 full extent, trying to envelope the object of its desire. 

 It failed again and again ; but renewed the attempt, 

 until at length, convinced of its hopelessness, it flung 

 itself away as if in disappointment, and made off in 

 search of something more manageable. With the 

 Amoeba are found other types of equally simple Pro- 

 tozoa, but somewhat differently organized. One of 

 these, Actinophrys (fig. 13), has the body globular and 

 unchanging in form, the outer wall of greater thick- 

 ness ; the pulsating vesicle like a blister on the surface, 

 and the pseudopods long and thread-like. Its habits 

 are similar to those of the Amoeba, and I introduce it 

 to show the variations of form and structure possible 

 even among these simple creatures. 



The Amoeba and Actinophrys are fresh water animals, 

 and are destitute of any shell or covering. But in the sea 

 there exist swarms of similar creatures, equally simple 

 in organization, but gifted with the power of secreting 

 around their soft bodies beautiful little shells or crusts 

 of carbonate of lime, having one orifice, and often in 



