Dr. M. Vevvvoi'ii's Biological Studies of Protista. 165 



bodies, such as paper-fibres &c. But what appears to rae to 

 be of importance is the circumstance that the Protista taken 

 up are killed. This distinctly indicates the occurrence of a 

 chemical action on the part of the fragment upon the proto- 

 plasm of the food-organisms. Unfortunately in most cases 

 it is very difficult to ascertain whether a digestive process 

 does or does not occur, and therefore I have communicated 

 this observation only because it may perhaps hereafter be 

 made available in connexion with others. 



In order to supplement my own investigations upon the 

 phenomena of regeneration in the Polythalaraia I will here 

 refer to the observations which Carpenter * had occasion to 

 make on the material of the ' Challenger ' Expedition. 

 Among the Foraminifera of the ' Challenger ' Expedition 

 Carpenter found some species of the genus Orbitolttes which 

 were remarkable for their considerable size. One species, 

 which he named Orhitolites tenuissima, grows to the size of 

 0'6 inch, and is characterized by an exceedingly thin and 

 brittle shell. The consequence of this peculiarity was that 

 among the specimens obtained only a few were uninjured ; 

 but, on the other hand, there were many which had repaired 

 earlier injuries. Carpenter gives the following description of 

 the mode of reparation : — " When only small portions of the 

 margin are broken away the next-formed annuli extend 

 themselves along the fractured edge ; and thus the cyclical 

 mode of growth is completely maintained with only a tem- 

 porary irregularity." And it is not only small injuries that, 

 according to Carpenter, are repaired in this form, but the 

 power of regeneration goes so far that even small fragments 

 can complete themselves to form perfect individuals, the outer 

 shell-convolutions of which then have exactly the normal 

 constitution. One of Carpenter's figures shows how such a 

 small fragment has completed itself into a perfect individual. 

 Carpenter says of it : — " I have been able to assure myself that 

 every part of the margin of this fragment — whether broken 

 or unbroken, peripheral, central, or lateral — has contributed 

 to the formation of the first new complete annulus, by which 

 the foundation was laid of the subsequent regular series of 

 concentric zones, thus clearly indicating that a sarcodic 

 extension took place from every chamberlet laid open by the 

 fracture, as well as from the normal pores of the last septal 

 plane, and that these extensions coalesced to form a con- 

 tinuous ring, as in the formation of the ordinary succession 

 of concentric annuli. It is most interesting to observe that 



* "Report ou the Speciiuens of the Genus Orhitolites &c.," iu ' Chal- 

 lenger ' Kt'port, vol. vii, 



