No. 2308. LIVING SPECIMENS OF IRIDIA DIAPHANA—CUSHMAN. 155 



lining could not be determined. These specimens had practically no 

 included algae. When such specimens have left their test they are 

 capable of extended and fairly rapid movement. One such speci- 

 men which had left its test voluntarily is shown in plate 20, figure 1. 

 It is elongate, with a definite "head" to the body and numerous 

 pseudopodia streaming behind, as well as a few in front. The "body" 

 portion with its pseudopodia formed a line more than an inch in length. 

 During its movement records of its rate were taken and these were 

 from 1 minute and 40 seconds to 2 minutes for a distance of a milli- 

 meter. Later other specimens were found to have a much more 

 rapid rate of motion as will be given. 



The movements and changes in this specimen seem worthy of 

 note. After traveling for a considerable distance in the elongate 

 form (pi. 20, fig. 1) it became concentrated into a more rounded form, 

 which semingly was about to divide into two portions by its con- 

 strictions, but later started out again, in an elongated form. These 

 (pi. 20, figs. 2-6; pi. 21, figs. 1-7) were drawn with camera lucida at 

 intervals while the whole protoplasmic mass was in slow but rather 

 steady motion. Toward the end of this series motion became less 

 rapid and nearly ceased, but later a clearer "tongue" of protoplasm 

 was thrust out (pi. 21, fig. 7) and motion again became became rriore 

 rapid. 



After the elongate form and more rapid movement had been re- 

 sumed portions were cut oft" with a scalpel. Where a small portion 

 of the end was severed, the detached mass quickly became globular 

 by concentration of the protoplasmic portions; then after a short 

 time numerous fine pseudopodia were sent ofl^ very rapidly in all 

 directions until fusion took place with the original mass, which also 

 during the same period had sent back numerous fine pseudopodia 

 from the direction of the cut. When fusion of the pseudopodia 

 takes place the smaller severed portion sets up a rapid streaming 

 toward the larger mass until the two are once more united, when 

 shape and motion are carried out as before. 



Where a small mass was removed and placed at some distance 

 from tiie larger mass the same process was repeated, but after 

 fusion was not made, owing to the distance, the smaller mass became 

 concentrated in a subspherical mass, where it remained c{uiescent 

 for two days, then gradually broke down and disintegrated. This 

 smaller portion probably had no nuclear material and was unable to 

 regenerate. Later on the larger mass of this particular specimen 

 approached a leaf of Posidonia nearly half an inch from the bottom, 

 and after sending out numerous pseudopodia gradually lifted the 

 body to the edge of the leaf and settled there. 



Numerous specimens v>^ere removed from their tests by cutting 

 away the chitinous layer at the base and taking the mass of proto- 



