THE INFUSORIA 



fragment then becomes encased in a spherical cyst. This is passed into 

 the water, and if it is then swallowed by a tadpole, gives rise to a 

 uninucleated spore which absorbs nourishment and grows. As it grows 

 the nucleus divides, and so the large inultinucleate form from which 

 it sprang is reattained (Figs. 53 and 54). 



The HYMENOSTOMATA are arranged by Schewiakoff as follows : 

 Family CHILIFERA, Butschli. Blepharostoma, Schew. With very 

 long peribuccal cilia. '015. Freshwater. Dichilum, Schew. With right 

 and left lips, the latter rudimentary. 0'03. Freshwater. Australia. 

 Trichospira, Roux. Freshwater. Dallasia, Stokes. Dorsal side concave, 

 ventral side convex. Very large mouth, just behind the anterior extremity. 

 Two undulating membranes. Swims on the concave dorsal side. O'l 4. 

 Freshwater. Plagiocampa, Schew. A lip on the left side only. A 

 border of labial cilia on the right. 0-04. Freshwater. Australia. 

 Uronema, Duj. Oval in form, slightly compressed. Convex on the 

 dorsal side. Flat on the ventral side, with an excavation in the 

 buccal region. Provided with a long caudal cilium. 0'07. Freshwater. 

 Stegochilum, Schew. Pharynx absent. Well-developed labial membrane. 

 0'07. Freshwater. Australia. Cryptochilum, Schew. Leucophrys, Ehrb. 

 Body compressed. Provided with a large, tongue -shaped, undulating 

 membrane. 0'25. Freshwater. Leucophrydium, Roux. Monochilum, 

 Schew. In the form of an elongated cylinder. Loxocephalus, Kent. 

 Undulating membrane doubtful. A single long cilium at posterior end, 

 also a row of specially long cilia on the right side. 0'05. Freshwater 

 and in infusions. Chasmatostoma, Engelmann. Kidney-shaped. 0'06. 

 Freshwater. Glaucoma, Ehrb. Oval in form, but slightly flattened. 

 Cilia evenly distributed. O'l. Freshwater, but principally found in 

 infusions. Urozona, Schew. Only the middle part of the body furnished 

 with cilia, which form a thick band encircling the body. 0'03. Fresh- 

 water. Colpidium, Stein. Oval or kidney-shaped. A large mouth 

 situated some distance behind the anterior extremity on the ventral side 

 of the body. Cilia evenly distributed. O'l 2. This genus and the next 

 (Colpoda) very common in freshwater infusions. Colpidium also occurs 

 in marine infusions. Colpoda, Miiller. Similar to Colpidium, but more 

 definitely kidney-shaped. The twist in the rows of cilia at the anterior 

 end is from left to right, the opposite of that in Colpidium. O'l. Very 

 common in hay infusions. Frontonia, Clap, and L. Large cylindrical 

 bodies or pointed posteriorly. On the right border of the mouth there 

 is a ciliated stripe, free from trichocysts. Colourless or green with 

 Zoochlorellae, sometimes provided with black or brown pigment. 0'35. 

 Freshwater and marine. Disematostoma, Lauterb. Philaster, Fabre Dom. 

 Ophryoglena, Clap, and L. 0'5. Freshwater. Blepharocorys, Bundle. 

 Coecum of the horse. 



Family MICROTHORACINA, Wrzesniowski. Cinetochilum, Perty. This 

 animal appears to swim upside down. During progression the extremity 

 which bears the mouth is posterior. It is provided with two vibrating 

 lips, of which the right is larger than the left. 0'04. Freshwater. 

 Microthorax, Engelmann. The mouth turned more to the right side than 

 in the preceding genus. 0'06. Freshwater. Trichorhynchus, Balb. One 



