MORPHOLOGY 



53 



Protozoa appears to be Lieberkiihn (1857) who noted the "muscle 

 fibers" in the ectoplasm of Stentor which were later named 

 myonemes (Haeckel) or neurophanes (Neresheimer). 



The myonemes of Stentor have been studied by several in- 

 vestigators. According to Schroder (1906), there is a canal between 

 each two longitudinal striae and in it occurs a long banded myoneme 

 which measures in cross-section 3-7m high by about l/x wide and 

 which appears cross-striated (Fig. 14). Roskin (1923) considers that, 



oe 



" 0^^< 



Fig. 15. a, b, fibrillar structures of the stalk of Zoothamnium (Kolt- 

 zoff); c, m}''onemes in Gregarina (Schneider), ef, elastic fiber; ie, inner 

 envelope; k, kinoplasm; oe, outer envelope; t, thecoplasm. 



the myoneme is a homogeneous cytoplasm (kinoplasm) and the wall 

 of the canal is highly elastic and counteracts the contraction of the 

 myonemes. All observers agree that the myoneme is a highly con- 

 tractile organella. 



Many stalked peritrichous ciliates have well-developed myonemes 

 not only in the body proper, but also in the stalk. Koltzoff 's studies 

 show that the stalk is a pseudochitinous tube, enclosing an inner 

 tube filled with granulated thecoplasm, which surrounds a central 



