1894.] MICllOSCOPICAL JOURNAL. 201 



terial I had under study provided me with living speci- 

 mens of Surirella splendida. A statement of some of 

 the phases observed by myself will enable me to sub- 

 stantiate and verify a part of the interesting researches 

 recorded by Prof. Smith. While searching through the 

 heavier sediment, I found one large living specimen of 

 Surirella splendida, the same form as figured and ob- 

 served by Prof. Smith. I made a continuous observa- 

 tion of this form for more than one hour, and therefore 

 got a good idea of its biological structure. While Prof. 

 Smith and Dr. Carpenter both refer to the genus Suri- 

 rella, or to particular species of Surirella, in terms such 

 as to indicate that their movements or travelling power 

 is insignificant in its character; I, on the contrary, 

 found that they were fully as active as Navicula major, 

 and required constant attention to keep them in the 

 field of view under a one-sixth objective, and as I studied 

 four distinct specimens of the larger Surirella on three 

 different evenings, I found that all moved about the 

 same as the larger Navicular and when they were not in- 

 tercepted by debris of the slide, would readily move 

 out of the field of view, the same as the other travellers 

 do. Carpenter alludes to their movement, as a " lanquid 

 roll " and Prof. Smith uses the terms " lazy sort of roll" 

 and elsewhere refers to its "lanquid roll," but from my 

 personal experience, I would assert that their actual 

 change of place is as full of interest as that of Navicular 

 and is of the same character, but with a greater tendency 

 to lose its balance while in motion, thus suggesting the 

 roll by a change of aspect in the position of the ala». 



While studying the motions of two of .the Surirella', 

 .while in the field, on two successive evenings, I closely 

 observed their behavior while working their way through 

 masses of debris intercepted in their movement. The 

 minute vegetal debris, etc., was simultaneously passed 

 from their anterior prows backwards continuously along 



