VorticelUna.] THE INFUSORIA. 253 



no pedicle or stalk, are free, but can attach themselves by 

 the posterior extremity of their bodies, which, assuming at 

 pleasure, the form of a cone, enables them to adhere to 

 various substances, like leeches. The body is entirely 

 covered with cilii, and a wreath of larger ones surmount 

 the fore part. The function of locomotion is performed 

 by their cilii, while their anterior wreath are likewise 

 special organs for purveyance. Ehrenberg considers the 

 longitudinal striae along the body, and the circular ones 

 at the anterior part, muscular fibres. The anterior wreath 

 of cilii are coiled up in a spiral form, near the mouth, 

 and in some species a row of long ones proceed from the 

 mouth, in a fringe-like manner, to the middle of the body. 

 The nutritive apparatus consists of numerous berry-like 

 stomach-cells, connected together, and presenting a moni- 

 liform or necklace-like alimentary canal, which proceeds 

 from the mouth along the body, and returns, uniting with 

 it in a spiral-shaped cavity. Oscillatoria, Rotatoria, 

 and Monads, are often found abundantly in the stomach- 

 cells. They increase by self- division, either longitudi- 

 nal or oblique ; also from ova ; these form a net-like 

 granular mass, cover the stomach-cells, and vary in 

 colour in different species ; they have also a gland- like 

 sexual body, resembling the soft roe of fish, whose 

 shape is band-like, moniliform, or round, and a contractile 

 bladder. 



All the species are visible to unassisted vision, and are 

 best examined between the plates of a large live-box, a 

 portion of the decayed stem or leaf on which they are 

 found being put in with them. 



384. Stentor MiiUeri. MilUer's Stentor. — This is the 



