3-^8 



The Ohio Naturalist. 



[Vol. V, No 6, 



total width of the peristome was about two-thirds of the adult 

 form. In two minutes more it had assumed the form shown in 

 Fig. 3, the posterior end had narrowed considerably and while 

 the constriction extending from the posterior ciliary wreath was 

 still one-third the total length of the body its attached end had 

 assumed the appearance of the adult pedicle. The lengthening 

 of this pedicle had every appearance of growth and not of meta- 

 morphosis of body into pedicle. The body while producing the 

 pedicle was actually larger than before, and although the form 

 was feeding rapidly it is hardly conceivable that assimilation and 

 growth could take place at the rate at which the pedicle appeared. 



J 



T 



(j-^eO 



DESCRIPTION OF PLATE. 



Fig. 1 



Four stages in the growth of the pedicle of Ephistylis flavicaus 

 Ehr. p. c. — posterior circlet of cilia, p. — pedicle appearing first 

 in Fig. 3. 



At the end of five minutes more (Fig. 4) the body of the 

 animalcule was nearly normal in every respect except that the 

 slight elevation on which the posterior circlet of cilia had been 

 situated could still be observed although the cilia had been 

 retracted. The pedicle at this time was one-sixth the length of 

 the body and the animalcule was feeding actively. From this 

 point on only the relative rate of growth in the pedicle will l)e 

 given as no opportunity offered to note any other histological 

 changes than those pertaining to the lenghtening of the pedicle. 



At the end of five minutes more or a total of fifteen minutes 

 in all the pedicle was equal to one-fourth the length of the body ; 

 in twentv minutes one-third; at twentv-five minutes one-half; 

 at thirty minutes, thirteen-twentieths; at thirty-five minutes, 

 four-fifths, and at the end of forty minutes equaled the bod)- in 

 length. 



It was not observed again for a period of forty-five minutes 

 during which time the pedicle had attained a length equal to 

 three times that of the body. This is somewhat under the nor- 

 mal, the unbranched pedicle usually being four to five times that 

 of the body. So that a period of one hour and a half was suf- 

 ficient to produce a pedicle nearly equal to the unbranched por- 



