MORPHOLOGY 



87 



chapter (p. 118). Comparative study of contractile vacuoles (Haye, 

 1930; Weatherby, 1941). 



Various other vacuoles or vesicles occur in different Protozoa. In 

 the ciliates belonging to Loxodidae, there are variable numbers of 

 Miiller's vesicles or bodies, arranged in 1-2 rows along the aboral sur- 

 face. These vesicles (Fig. 31, a-c) vary in diameter from 5 to 8.5/* 



Fig. 30. Excretory canal of Haptophrya michiganensis (MacLennan). 



a, an individual in side view, showing a contraction wave passing down 

 the canal; b, successive views of the same region of the contractile canal 

 during a full pulsatory cycle (a-c, systole; d-g, diastole); c, diagram show- 

 ing a contractile wave passing from left to right between two adjacent 

 excretory pores. 



and contain a clear fluid in which one large spherule or several small 

 highly refractile spherules are suspended. In some, there is a fila- 

 mentous connection between the spherules and the wall of the 

 vesicle. Penard maintains that these bodies are balancing cell-organs 

 and called the vesicle, the statocyst, and the spherules, the stato- 

 liths. 



Another vacuole, known as concrement vacuole, is a character- 

 istic organella in Biitschliidae and Paraisotrichidae. As a rule, there 

 is a single vacuole present in an individual in the anterior third of 

 body. It is spherical to oval and its structure appears to be highly 



