STUDY OF THE GENICULA OF CORALLINE. 3g 



communicating with one another through the pores in Jania ruhi-ns. 

 Wille 13 also mentions this character and seems to believe that pro- 

 bably all species of Amphiroa and Gorallina have the same sort of pores. 

 As will be understood from the present study, the pores in the cell- 

 walls are limited to a certain group of the Corallinœ. Some of 

 Amphiroa have the pits and most of the Eurytion have the bordered 

 pits. This will be described more in detail. 



Amp. (lihttata, Amp. Boiverbankii, etc., are those which have the 

 bordered pits. These pits are found at the distal ends of the periclinal 

 cells in like manner as the connecting plates in the other species, and 

 also at the periclinal sides of the cells. They are exactly similar in 

 the structure to those found in the Conifers (fig. 12). The large 

 openings just mentioned above are not met in these species. 



The bordered pits in the periclinal sides are almost always at 

 points nearly one third of the length of the cells from the upper ends, 

 as has been formerly remarked. Hence the pits, in a meridional 

 section of a frond, are seen disposed in rows parallel to the zones of 

 the cell connection. About the fate of the pits a brief account has 

 already been given (p. 32). 



There is an interesting parallelism in the pits of the land plants 

 and the CoraUiiur. In the land plants the pits are normally found in 

 such groups as Coniferœ, Dvimys, Troclwdendron, etc., which are pro- 

 vided with poor vessels or none at all. 2) It has not been hitherto 

 described, as far as the present writer's knowledge extends, in the 

 lower cryptogamic cells. The principal part of the translocation of 

 the nourishment is played through the thin membrane of the pits. 

 Algœ as a whole have no kind of the vessels and all communication 

 must be furnished by the openings between the cells. And these 



1). Bidrag till Alg. Phys. nat. p. 40. 



2). Strasburger: Ueber d. Bau u. d. Verrichtungen d. Leitungsbahnen. p. 161. 



