114 



-lie calls a thallus; it consists of several rows of cells originating 

 from a single row of long cylindrical cells, and terminating also 

 in a single row, the upper one of which is not an apical cellj as 

 in case of Sphacelaria, but grows out to a long hair-like appen- 

 dage; subsequent growth in length takes place by intercolary 

 cross division of single cells. The manner of branching is fully 

 described, but the chief interest from a systematic standpoint 

 lies in the manner of reproduction, which in this genus appears 

 to be non-sexual. The organs of reproduction are termed spor- 

 angia and occur either as end cells of side branches, which 

 take the place of the hair-like projections, or in certain cases the 

 sporangium branch is reduced to a single cell, and even in some 

 instances the reduction goes so far that a vegetative cell of the 

 main branch becomes a sporangium. In the early stage of this 

 cell it is filled with a homogeneous, granular substance Avhich fills 

 the space between the nucleus and the chromatophores pressed 

 against the wall. In the next stage are found numerous small 

 bodies which he names mucilage bodies, and others resembling 

 those in the brown algae ; these are separated more or less regu- 

 larly by fine walls of granular protoplasm. 



The nucleus now divides, the two nuclei again divide, they 

 separate from each other, and at this stage a thin membrane is 

 formed around the contents of the sporangium, lying close to the 

 wall of the latter. This wall now breaks and the spore escapes 

 with its new mrmbrane and its four nuclei. It begins to germi- 

 nate at once, the single cell dividing into four, and by subsequent 

 divisions a small tuber-like body is formed from which arises the 

 stem or thallus of a new plant. Some variations from this pro- 

 cess are recorded, but this he claims to be the normal method. 

 Concluding the description of this plant, the author says that 

 he has examined hundreds of this species and does not hesi- 

 tate to affirm that its method of reproduction is wholly non-sexual 

 If an analogy between this and the browm algae is sought for, 



fc."- *^ -•^"to 



it may be found in the similarity of vegetative structure which 

 exists between this and the genera Sphacdaria and Ec/ocarptis. 

 In the method of reproduction, however, it is most like the te- 

 traspore-producing Dyctyocea:;. In both the spores are sexually 

 produced ; in both kinds of spores are four nuclei which result 



