232 



HARDWICKE'S SCIENCE-GOSSIP. 



is a fringe of long vibratile cilia, which is used by the 

 organism when it swims freely about. Trichodina, 

 although usually described as parasitic, does not 

 appear to be so, for the mouth is situated on the 

 upper surface, between a disc and peristome, in a 

 similar manner to Vorticella, and the "bell" can be 

 opened and closed by a similar mechanism. Indeed 

 the organism resembles a free Vorticella bell newly 



which it is attached. The organism somewhat re- 

 sembles Vorticella, but the oesophagus is ciliated. In 

 the interior their are green particles. The length of 

 this organism is about the two-hundredth of an inch. 

 37. Cothurnia maritima (Fig. 142, B) and the 

 other species of this genera much resemble the pre- 

 ceding. The carapace or case is, however, stalked, 

 and fixed by the blind extremity. The length of this 



Fig. 141. — Zoothamnium spirale. A, Low power extended, b, Low power contracted, c, High power, d, EiUtylis nutans. 



Fig. 142. — A, Vaginicola crystallina. E, Cothurnia maritima. 



cast off from the stalk. The sucker-like arrangement 

 must be considered as representing the stalk of 

 Vorticella. 



The genera Vaginicola and Cothurnia both live in 

 a case. 



36. Vaginicola crystallina (Fig. 142, A) is also 

 known as Cothurnia crystallina. The case, into 

 which the animal sometimes retreats, is shaped like a 

 vase (urceolate), and is sessile on the filament to 



species is about the two-hundred-and-fiftieth of an 

 inch. As the name implies, it is a marine species. 



C. inerbis inhabits fresh-water. 



38. Scyphodia (Fig. 143, a) is another genus of the 

 Vorticellince, and the specimen shown in the illustra- 

 tion was found attached to a Cyclops. Another 

 species of the large family of Vorticellina is shown 

 in Fig. 143, B ; it was furnished with chlorophyll 

 corpuscles. 



