356 



Dr. D. Ellis. 



[May 17, 



uniformly distributed. As cell-division takes place only in one direction of 

 of space, and transversely to the long axis of the thread, pressure is 

 generated along the long axis of the thread, with the result that the sheath 

 splits open at the apex. 



Multiplication. — Entirely limited to the rejuvenescence of single cells or 

 thread-fragments, which become detached and grow into new plants. No 

 sexual or asexual spores are formed. In the case of motile threads, fragments 

 are cut off, which grow into new threads ; the same process takes place in 

 the attached threads, the fragments being usually straight, but occasionally 

 spiral in form. Such fragments contain usually from one to seven cells. 

 Another variation of the same method in the case of attached threads is by 

 the liberation, through the open apex of the sheath, of single, either motile 

 or non-motile, cells. These cells grow into new threads. In the species 

 under investigation, both the independent motile cells and the cells of the 

 motile thread-fragments possessed polar cilia. 



Spiral Threads. — Under certain conditions of growth Cladothrix liberates 

 single cells or fragments of threads, composed of several cells, which 

 immediately on liberation assume a spiral form, move in an undulating 

 manner, and develop polar cilia. 



Formation of Cocci. — In the author's cultures such formations were not 

 observed. 



Artificial Cultures. — The artificial cultures instituted for confirmatory 

 purposes showed the accuracy of Hoeflich's observations. 



Motility and Organs of Movement. — The cells of the variety investigated by 

 the author, when motile, in all cases owed their motility to cilia that were 

 situated in a polar position, thus differing from the Continental varieties, in 

 which the cilia are placed in a sub-polar position. Straight motile threads 

 possessed one to three cilia at the poles of each cell composing the thread. 

 Spiral motile threads, on the other hand, possessed one to three cilia only at 

 the ends of the whole thread, the intermediate cells being devoid of cilia. 



Organs of Attachment. — So far as could be observed the attached threads 

 were held only by their own mucilaginous secretions. 



Phylogenetic Position of Cladothrix dichotoma. — The most closely allied 

 organism is Sphmrotilus natans, the connection of which is so close that it 

 must be regarded as a variety of Cladothrix. The investigation shows that 

 morphological as well as physiological varieties of this widely distributed 

 organism exist. The relationship to Streptothrix is an extremely distant 

 one ; in habits, methods of reproduction, and structure, Cladothrix is closely 

 related both to the Cyanophycese and to the lower bacteria 



