1870.] 211 [Edwards. 



view, and then, becoming entangled with two others, which likewise 

 were made up of many individuals, some eight or ten of its frustules 

 (as the complete individuals are called) were twisted around almost 

 off from the rest, so as to lie at right angles to them, and when the 

 group containing the largest number of frustules receded to their former 

 position, which they soon did, the eight or ten seeming by the act of 

 twisting to lose their power of motion among themselves for the time 

 being, were dragged along in a helpless condition, and twisted com- 

 pletely around one revolution, so as thereafter to fall back again into 

 their places, when all went on as usual. That is to say, the regular 

 motion of all the frustules over each other succeeded. Now what 

 kind of a joint can it be that permits of such eccentric movement ! 

 As I have already said, I am more puzzled than ever. 



For sometime back a discussion has been taking place in some of 

 the European journals as to whether this plant be an inhabitant of 

 fresh or brackish water. What I have observed points to the fact 

 that it will live in either. I have collected it in brackish water at 

 Hoboken, N. J.; my Weehawken collection was from a ditch con- 

 necting directly with the salt water of the Hudson River at its 

 mouth, and some years since I gathered it in the sweet fresh water of 

 the Fishkill creek,, along with Desmids and other truly fresh water 

 plants which, as far as we know, will not live in water containing any 

 appreciable amount of salt, and then, also, in winter and under the 

 ice, but nevertheless in an active condition. And I have taken my 

 salt water Weehawken gathering and diluted it with several times its 

 volume of fresh water, and yet it seems to floui'ish after many days, 

 and the Bacillaria is apparently more active than when first pro- 

 cured. So, also, the other Diatoms- which are present along with it 

 evidently profit by the change, for they have increased rapidly and 

 are in vigorous motion. 



Along with the Bacillaria in the brackish water at Hoboken, I 

 found numerous individuals of an AmpJiora, which I have known in 

 this neighborhood for many years, and which I considered unnamed 

 as yet. To it I have given the provisional name of A. lanceolata, on 

 account of the form of its outline. This genus has always been con- 

 sidered an epiphytaceous one; that is to> say, one which grows attached 

 to other plants or submerged substances, yet this form was free and in 

 active motion. In fact I think it was one of the most lively Diatoms 

 I ever saw. So another smaller species of Amphora Avhich is common 

 near here, is always, as far as I have noticed, free. Here we have 



