366 Mr. P. H. Gosse on Locomotion in the Foraminifera. 



represented in my outline figure of the species*, which was 

 taken from the living animal. Very frequently these tiny atoms 

 were found, in the morning, two, three, or even four inches up 

 the sides of the perpendicular glass vases, having crawled this 

 distance in the course of the night. And they never remained 

 long stationary ; the next morning would find them in some 

 remote part of the glass. The night was manifestly their time 

 of activity. 



After my return to London, all through the spring and early 

 summer, one of my tanks was literally swarming with a species 

 of Polymorphina ; the individuals increasing immensely and 

 rapidly by generation, or perhaps by gemmation (for, being very 

 much pressed with other work, I had not time to investigate the 

 interesting problem of their mode of increase) ; although, when 

 I stocked the tank, I was not cognizant of the presence of any ; 

 the fruitful parents of this abundant progeny having doubtless 

 been introduced in some tuft or tufts of weed. 



The individuals were of various dimensions; a large number 

 having quickly attained the adult size, viz, about y'^th of an inch 

 in length. They studded the sides of the vessel, the stones, and 

 the slender weeds, adhering to the filaments of the latter in such 

 profusion as to cover the whole contents of the vessel with white 

 dots, conspicuous even upon the most cursory glance. These, 

 like the Polystumellce, were constantly roaming ; they crawled up 

 and down the stems and branches of the Algse, and over the 

 various objects in the tank, never remaining long in one station. 



On removing one from the vessel (which I did frequently) to 

 an aquatic cell or ' live-box,^ for microscopic examination, it was 

 found to be entirely withdrawn; but, in the course of a few 

 minutes, the pseudopodia were seen to be protruding their tips ; 

 and then they gradually (so gradually that the eye could not 

 recognize the process of extension) stretched and expanded their 

 lines and films of delicate sarcode, till, in the course of a few 

 hours, these would sometimes reach almost from side to side of 

 the glass cell. The extension was principally in two opposite 

 directions, corresponding to the long axis of the shell ; though 

 the branched and variously connected films often diverged con- 

 siderably to either side of this line, giving to the whole a more 

 or less fan-like figure. 



Though the array was so very deliberately put forth, it was 

 very rapidly withdrawn on any disturbance to the animal ; as 

 when the water was agitated by slightly moving or turning the 

 cover of the cell. 



I am quite certain, from manifest (though small) changes of 



* Marine Zoology, vol. i. p. 13. fig, 14. 



