40 NATURAL HISTORY 



of an inch in diameter, is generally of a bright red colour, 

 of a globular form, with a small diaphanous tube pro- 

 truding from one side, and slightly enlarged at its ex- 

 tremity, like a trumpet : its length is equal to the dia- 

 meter of the animalcule. This pipe, I am inclined to 

 believe, is its sucker, or proboscis, by which it imbibes 

 nourishment. In swimming, it oscillates in front of the 

 animalcule. They are found, during the spring and 

 autumn, along with the green Cercaria, and are the prey 

 of the genus Bursaria. 



27. VoLVOx granulum. The grain Volvox. — Muller 

 defines this animalcule to be spherical, of a green co- 

 lour, with a bright circumference. 



The centre is of an opaque green, surrounded by a 

 transparent annulus. It is found in marshes during June, 

 and has a slow motion. See figure 13, 



28. Yohv ox globulus, {Doxococcus globulus, E.) — The 

 ball Volvox, This animalcule is nearly ten times the 

 size of the atom monad, or about 1 -860th of an inch in 

 diameter : it is placed by Ehrenberg immediately after 

 the monads, though he has not demonstrated the polygas- 

 tric form of its stomach ; it is globular, but sometimes 

 slightly egg-shaped : the hinder part is generally opaque, 

 probably from the food it contains : its motion is slow 

 and fluttering, but when disturbed is more rapid. 



29. VoLvox pilula. The pill Volvox. — A small round 

 transparent animalcule, with green spots. The circum- 

 ference is usually of a yellow green colour. A magnified 

 view of it is shewn at figure 14 : the upper part, marked 



