210 The Philippine Journal of Science lais 



Subphylum INFUSORIA — Continued. 

 Class Ciliata — Continued. 



Order Holotrichida — Continued. 



Suborder Trichostomina — Continued. 



Family Paramecidae — Continued. 



posterior half of the body. Typical genus, Paramecium Stein, 

 1860. 



Family Pleuronemidae. — A long peristome runs along the ventral 

 side terminating at the mouth. The body is compressed 

 laterally or dorso-ventrally. An undulating membrane borders 

 the entire left edge of the peristome and sometimes extends 

 around its posterior extremity to form a pocket leading to 

 the mouth. A less highly developed membrane borders the 

 other lip of the peristome. A well-developed pharynx may 

 or may not be present. Typical genus, Pleuronema Dujardin, 

 1841. 



Family Isotrichidse. — A group of interesting parasites found in the 

 stomachs of ruminants. The group recently reviewed by 

 Sharp ■"' in an excellent paper. Some of the members of this 

 group are of exceedingly complex structure. The bodies are 

 plastic, the cuticle thick and provided with evenly distributed 

 cilia. Mouth and distinct pharynx. The family includes the 

 genera Isotricha, Dasytricha, Biitschlia, Cyclopostliium, and 

 several others. Stein "^ designated the Family Ophryoscolecidae 

 to include organisms of the same general type. The student 

 is referred to Sharp's paper for further information. Typical 

 genus, Isotricha Stein, 1859. 



Family Opalinidae. — The oval bodies may be short or even stumpy 



or they may be long and wormlike. Mouth and pharynx 



absent. Typical genus, Opalina Purkinje and Valentin, 1835. 



Order Heterotrichida. — In organisms included in this order the ciliation 



is uniform. There is an adoral zone consisting of short cilia, 



which are fused to form membranelles. 

 Suborder Polytrichina. — The coating of cilia is uniform. 



Family Plagiotomidae. — Narrow, furrowlike peristome generally 

 beginning close to the anterior end and running back, ven- 

 trally, to the mouth, which usually lies between the middle 

 and the posterior end of the body. The adoral zone is usually 

 straight and is placed along the left side of the peristome. 

 Typical genus, Nyctotherus Leidy, 1849. 



Family Bursaridae. — Body usually short and pouchlike, but it may 

 be elongate. The peristome is in the form of a broad and 

 deep triangular area, the apex of which is at the mouth. The 

 adoral zone lies on the left edge of the peristome and may 

 extend over to the right anterior edge. Typical genera: Bur- 

 saria 0. F. Miiller, 1773; Balantidium Stein, 1867. 



^ Sharp, Robert G., Diplodinium ecaudatum with an account of its 

 neuromotor apparatus, Univ. Calif. Pub. ZoiJl. (1914), 13, No. 4, 43. 



^ Stein, F., Ueber mehrere neue im Pansen del Wiederkauer lebende 

 Infusionsthiere, Ahh. d. Kais. Bohm. Ges. Wiss. (1858), 10, 69; cited by 

 Sharp. 



