General Morphology o£ the Protozoa 21 



fibrillar systems (64, 132, 211) referred to as neuromotor apparatus, 

 silver-line system, neuroneme system, and infraciliature by different 

 workers. These "systems" have been demonstrated by various techniques, 

 so that it is difficult to correlate each one with all the others. In general, 

 however, the neuromotor system seems to be both endoplasmic and 

 ectoplasmic while the other fibrillar systems occupy a superficial position. 



Fig. 1. 12. Silver-line systems (after Klein). A. Prorodon teres; narrow- 

 mesh type with some orientation of filjrils. B. Primitive narrow-mesh type. 

 C. Striation-system in Cyclidiutn glaucoma. D. Double striation-system in 

 Cinetochilum marmritaccum. 



Neuromotor apparatus 



The neuromotor system of Euplotes (79, 209, 212, 238) includes a 

 relatively small number of fibrils (Fig. 1, 13, G). Those from the anal 

 cirri converge anteriorly in a "motorium," from which a membranelle 

 fibril passes anteriorly and to the left, and then posteriorly beneath the 

 peristomial membranelles. In addition, groups of fibrils extend from the 

 basal plates of the frontal and ventral cirri into the endoplasm. Although 

 the first and second frontal cirri are joined by such fibrils, no intercon- 

 nections have been demonstrated for the other cirri (79). A comparable 

 neuromotor apparatus has been described in other ciliates (211). 



Silver-line system 



The observations of Klein (132, 134) and others have revealed a 

 silver-line system, in many ciliates. The name of the system is derived from 

 Klein's technique, in which reduced silver is deposited on superficial 

 structures. The argentophilic "silver-lines" are assumed to be plastic 

 structures having the capacity to grow, split, undergo resorption, and 

 then reappear (132). 



The primitive system is a narrow-mesh (0.75-1. 0|j.) network containing 

 the basal granules (Fig. 1. 12, B). The fibrils themselves extend through 

 the interstices of the ectoplasmic alveoli. Since a narrow-mesh network 

 has been reported in Dileptus, Oxytricha, Epalxis, Spirostomum, Stentor, 



