478 Mis3 S> Gr. Foulke on Trachelius ovum. 



highly vacuolate. My own observations had coincided with 

 those of Mr. Kent, and recently strong confirmation of his 

 opinion was obtained from the following phenomena: — 



I had taken from a Chara-hog numbers of Trachelu. 

 Their unusually large size — one fortieth of an inch — afforded 

 special advantages for observation. In colour the specimens 

 were a transparent creamy yellow. When first removed to 

 the live-box they uniformly showed the ventral side to be 

 flattened and deeply indented longitudinally, so that a trans- 

 verse section would be kidney-shaped. After a confinement 

 of some minutes they became globose in contour, and thus 

 they remained during captivity ; but when they were set free 

 the indentation soon reappeared. In one specimen the granular 

 reticulation, at first finely shown, seemed to become less pro- 

 fusely ramified, and a current of the protoplasm towards the 

 central mass was noticed. This flow continued until all the 

 smaller branches were massed at a subcentral point, leaving 

 the rest of the body apparently hollow. One pseudopodium- 

 like process was now sent to a more posterior point in the 

 periphery, and the flow was resumed, this time outwards, 

 until the protoplasm was collected into a nodule attached to 

 the cell-wall, along which a small portion flowed, afterwards 

 remaining motionless. No nucleus could be detected in this 

 specimen, though present in all others examined. 



The alDOve condition remained unchanged for nearly an 

 hour, when, wishing to test the apparent hollowness of the 

 cell, I removed from the live-box all but a small portion of 

 the water, and pressed the Trachelius with a blunt knife-blade. 

 Complete collapse ensued_, and the animal now resembled a 

 twisted rag. 



It seemed, however, nowise injured by the operation, as, 

 after about six hours passed at the edge of the water, it 

 resumed its globose shape, and free motion about the live-box 

 again began. 



An accident prevented further investigation, but, from the 

 difl'uscd condition of the nucleus, incipient reproductive phe- 

 nomena were suspected. 



In this connexion I should like to draw attention to a form 

 described by me in a communication to the Academy of 

 Natural Sciences of Philadelphia, March 4th, 1884, under 

 the name of Trachelius Leidyi. The distinction then made 

 with regard to shape having been rendered invalid by the 

 observations above noted, colour and the more profuse vacuo- 

 lation of the periphery alone remain, and, regarding these as 

 insufficient differences, I have decided to withdraw the species. 



