1920] Taylor: Neuromotor Apparatus in Euplotcs 425 



The attachment of the cirri will be discussed in connection with a 



description of the neuromotor apparatus. It remains here to describe 

 briefly the several movements that are common to the different groups 

 of cirri. Putter (1903) discusses these general types of ciliary move- 

 ments among Protozoa: (1) the "book-like" type, found in cilia or 

 flagella used for food-taking; (2) the "whip-like" type, exemplified 

 by the flagellum of En<ilcna, and (3) the "infundibular or funnel- 

 like" type, very common among most flagellates and ciliates. The anal 

 cirri of E. patella frequently exemplify types both (1) and (2), while 

 types I 2) and (3) are common for their frontal, ventral, and marginal 

 cirri. Yocom's observation (PUS. p. 363), that the anal cirri "move 

 in only one plane, that parallel to the median plane of the body," is 

 hardly adequate. As will be described presently, these cirri are very 

 frequently used in guiding the animal to the right or left, and are 

 especially active as the chief means for making sharp turns to the 

 right, which i.s not an uncommon reaction during swimming. In the 

 latter instance, particularly cirri 3, 4, and 5 (numbering from left to 

 right) are flexed rather abruptly near their base and lash close along 

 the ventral surface of the body. Griffin (1910, p. 301) regarded the 

 anal cirri of E. worcesteri to have "only a single, strong motion: a 

 vigorous kick directed backwards." In E. patella, however, this back- 

 ward stroke is by no means the only effective movement, nor even the 

 most important. The "avoiding reaction" of this species, which will 

 he described further on, is effected chiefly by means of the anal cirri. 

 Furthermore, these cirri, together with the frontal and ventral groups, 

 are the animal's "feet" for creeping and, as we shall see later, upon 

 removing the anal cirri, creeping becomes impossible. 



Another common use of these anal cirri may be observed in their 

 attachment to suspended debris in the water and swimming about with 

 it sometimes for several minutes; or, less frequently, in holding on to 

 floating debris or even to the dissecting needle and suspending tin- body 

 dorsal side down, occasionally at an angle of fifteen degrees or more. 

 The attachment, to the needle at least, is usually with two or three and 

 often four anal cirri. In such eases I have observed clearly a slight 

 flexure of the tip of one or more cirri about the needle and had con- 

 cluded this to be the means of supporting the body; but later, an 

 attachment by only one cirrus was seen with the tip several microns 

 in length lying along the under side of the needle. This latter obser- 

 vation has since been made a number of times and in two instances I 

 was able to move the needle slowlv back and forth without disturbing 



