352 Transactions of the Society. 



X. — On Certain Filaments observed in Surirella hifrons. 

 By John Badcoce, RE.M.S. 



(Read Qth April, 1884.) 



On the 5tli April I collected some very fine diatoms from the 

 noted Keston bog, among which examples of Surirella hifrons were 

 very conspicuous, both by their abundance and size, and also by 

 their very clean and active condition. 



Selecting one for special attention, I noted that in its passage 

 across the field it would occasionally pass close to certain small 

 collections of vegetable debris (but without actual contact), when 

 these small matters seemed to be caught by some projecting fila- 

 ment from the diatom, by which they were carried along with it for 

 some distance. Then the diatom would free itself, but, coming in 

 contact in the same manner with other similar material, the same 

 thing would happen again. 



Observing this very often with only a 2/3 in. objective, I tried a 

 higher power. With the 1/4 in. I could not discover any more 

 than before the cause of the phenomenon. At length, however, 

 with a 1/2 in., which had been altered for use with the binocular 

 arrangement, I discovered certain fine filmy processes projecting 

 irregularly from the diatom, and which appeared to have caused this 

 disturbance. Further and repeated observation confirmed my 

 conviction of a correspondence between these projecting filaments 

 and the disturbances noted, the significance of which could not 

 be mistaken. 



I now called my son, and asked him if he saw anything 

 exceptional, and to sketch it for me. This he did, as shown in 

 figs. 49 and 50. The filaments were seen repeatedly and very dis- 



FiG. 49. 



tinctly by both of us, whether the front or the side of the diatom 

 was in view. 



My attention was not confined to one diatom only. The 

 appearance showed itself in many, but not in all, and there was 

 a very perceptible difierence in its development in difierent 

 specimens. 



1 had been observing some Arcellina from the same gathering 



