Euchlanidota.} T HE INFUSORIA. 383 



species. No male organs, vessels, nor respiratory tubes, 

 are seen. Owing to the almost constant vibration of the 

 foot-like tail, it is difficult to observe the true form of its 

 termination, the motion producing an optical deception ; 

 hence it appears double, though in reality it is single. 



655. MONOSTYLA cornuta (Trichoda cornuta, M.) 

 The smooth Monostyla. Lorica hyaline, unarmed, and 

 truncated anteriorly. Found amongst chara and conferva. 

 Length 1 -250th. 



656. MONOSTYLA quadridentata. The four-horned 

 Monostyla. Lorica yellowish, the anterior deeply dentated, 

 resembling four horns. It is generally of a yellow leather 

 colour, but Ehrenberg has seen it colourless. Figs. 434 

 and 435 represent ventral views of this animalcule ; the 

 latter is extended beyond its lorica, which happens when 

 the rotatory cilii are in motion. Fig. 436 is a side view, 

 and Jig. 437 the jaws and teeth separate. Found in 

 floccose matter about conferva and the leaves of water- 

 plants. Length l-120th. 



657. MONOSTYLA (?) lunaris. The moon-shaped Mo- 

 nostyla. Lorica hyaline, the anterior crescent-shaped. 

 Length 1-1 44th. 



Genus CLXIX. MASTIGOCERCA. The whip-tailed 

 Rotatory Animalcule is characterized by its having a single 

 cervical eye, a simple styliform foot, the lorica prismatic 

 and crested on the back. It has a four-partile rotatory 

 organ, a small muscle to move the foot, an oblique ceso- 

 phagal head, with unequal jaws, two-toothed; a short 

 oesophagus, simple intestine, with two spherical glands, a 

 globular ovarium, a contractile vesicle, and a long- 

 ganglion. 



