358 University of California PuMicaUons in Zoology [Vol. 18 



When stained this structure is colored the same as the fibers and 

 motorium with the acid fuehsin of the Mallory's stain. However, 

 many of the specimens stained by the haematin do not show this 

 structure so distinctly ; but this is due to the fact that the lip is so 

 thin that the stain is all removed before other parts of the organism 

 are destained sufficiently for study. Thus it is seen that the lip con- 

 tains a structure not only similar in its chemical reactions to the other 

 parts of the neuromotor apparatus, but also in its anatomical relation- 

 ships it is shown to be an integral part of the system, and a part which 

 seems likely to furnish some very important evidence indicating the 

 nervous function of the neuromotor apparatus, for all relations point 

 to the conclusion that this structure lacks both motor and skeletal 

 functions and that it functions as a tactile sense organ in connection 

 with the anterior cytostomal membranelle. 



The last part of the neuromotor apparatus to be described is the 

 system of fibers in connection with the frontal, ventral and marginal 

 cirri. This system of fibers will be described as a dissociated part of 

 the neuromotor system, for in the dozens of specimens studied there 

 has been no indication that the fibers in connection with the frontal, 

 ventral and marginal cirri are in any way connected with the motorium 

 or any part of the neuromotor apparatus described in the preceding 

 paragraph. 



The arrangement of the fibers of the dissociated part of the neuro- 

 motor apparatus differs greatly from that of the fibers in connection 

 with the five anal cirri. Instead of each of the frontal, ventral and 

 marginal cirri having a single fiber as the anal cirri, they are joined 

 by several much finer and shorter fibers. These fibers range in number 

 from four to six extending out in one direction from some of the cirri 

 to two or three groups of four or six, each extending out in different 

 directions (/. c. /., fig. A). Some of these groups in comiection with 

 the frontal and ventral cirri may overlap each other, but in no case 

 has there been any indication that the fibers from one cirrus join 

 any other cirrus or the fibers from it. In case of the marginal cirri 

 there is only one group of fibers connected with each cirrus and these 

 extend anteriorly and never overlap. These fibers do not join any 

 structure other than the cirri, but as they extend out into the cyto- 

 plasm they become finer until they are finally lost to view. Prowazek 

 (1903) described such a system of fibers for Euplotes harpa, but he 

 also pictures a system of fine fibers in connection with anal cirri in 

 addition to the five longitudinal fibers. The latter system of fibers in 



