1921] NATURAL SCIENCES OF PHILADELPHIA. 129 



to be expanding upwards ; at 1 1 h . , 45 min. , the collar was normal again, 

 and the flagellum, which had for a time disappeared from sight, 

 extended freely in the axis of the funnel. 



The overflowings of plasmatic matter, which are frequently met 

 in this particular species, are very little known; in some forms 

 similar facts have been mentioned, and Burck, who, however, did 

 not happen to meet with any such cases, speaks of the subject in 

 the following words: "I have not found in normal individuals such 

 formation of pseudopodia as Sav. Kent says he sometimes met 

 with. According to this observer, Choanoflagellata may even pass 

 through amoeboid stages. Zacharias assigns some importance to 

 the pseudopodia in the capture of food, and does not hesitate to 

 call them organs of prehension. France also observed Lobopodia 

 in several places on the body. In my opinion such structures occur 

 only in wounded individuals, which are not far from death." 



I do not think such occurrences must necessarily be associated 

 with a state of disease, but could not help sometimes observing a 

 certain coincidence between the development of these pseudopodia 

 and the abundance of food, the animalcules capturing then with 

 increased quickness very small special organisms (sulfureous algae?) 

 which were extremely abundant all around. But this way of cap- 

 turing food is certainly exceptional; the nutritive elements are 

 mostly thrown down straight upon the plasmatic funnel, either on 

 its outer surface or more often on the inner surface. When the 

 prey are very small, they seem to be digested inside the wall of the 

 collar itself; a small shining globule, for instance, such as was mostly 

 the case, was seen to lose by and by the sharpness of its outline, 

 then to swell up, turn pale, and at last disappear, without having 

 moved at any time from the place it occupied. But when the prey 

 are caught quite near the bottom of the funnel, a vacuole immedi- 

 ately foi-ms around them, and they are quickly seen to disappear 

 downwards. In one particular case, I saw a small shining particle 

 fall on the naked neck of an animalcule that had not yet constructed 

 more than half its shell; it was immediately caught in a vacuole, 

 and slowly slipped down along the surface of the body, to stop after 

 five minutes quite near the posterior extremity (Plate VI, fig. 33). 

 The downward course seemed to have been effected in a spiral line, 

 but I no more than Burck could detect the least sign of a fine spiral 

 tracing, itself representing, as France will have it, the border of a 

 spirally coiled funnel. 



