Further Observations ou Koenenia. ;411 



and sometimes not only tlie flagellum but the abdomen would be 

 bent back so that only the liead and thorax remained parallel with 

 the surface on which they walked. This gave the animal the ludi- 

 crous appearance of attempting to stand on its head. The Koenenia 

 seemed very sensitive to the approach of other individnals of the 

 some species. They would dart apart, when with the lens I could 

 not see that they liad tonched, as if each had received a shock. The 

 warning- of approach must have been given by the delicate sensory 

 hairs on the third pair of appendages. which are evidently extremely 

 sensitive. Offen when one of these little aninials was running. the 

 flagellum dragged, seeming- to hug the soll. The long- setae on the 

 organ probably served them in making their position more secure. 

 This was noticed most particularly when catching- them with a brush; 

 if the flagellum touched the hairs of the brush and lay parallel 

 with the hairs, much shaking was necessary to dislodge the animal, 

 while in several cases I have been forced to cut a few hairs of this 

 brush and leave them with the Koenenia. These setae have more 

 power of movement than one might suspect. On dropping a live 

 specimen in a 8yracuse watch-glass containing alcohol, I have seen 

 the animal in its death struggles. throw the long plumulose setae 

 down tili they lay pressed for their whole length. save the bent 

 area near the tip. against the flagellum. In this condition the 

 flagellum sometimes breaks off and the hairs remain in the appressed 

 Position. Offen, however. the hairs return to the normal position or 

 are thrown far forward making anteriorly an acute angle with the 

 flagellum. 



While the aninials were running about the motion of the cheli- 

 cerae could not be observed but when a live specimen was placed 

 under the microscope the movements of these appendag-es were 

 I extremely interesting. There was almost perpetual motion of the 

 movable distal Joint — as automatic as the avicularia of Bugula 

 but much more rapid. Occasionally it would grasp one chelicera with 

 the other very much in the manner of a person wringing- his hands. 

 There was another movement in which the two distal joints were 

 drawn up under the mouth, and then to all appearances the comb-like 

 hairs, projecting over the mouth from the basal Joint of the 

 chelicera, were drawn through the teeth of the claws. Up to this 

 time I have not had the good fortune to see Koenenia use these 

 appendages in obtaining food. The chelicerae like the corresponding- 

 appendages in the spiders, harvestmen, many Acarids and the Solpugida, 



