— 247 - 



Harvey in "Nereis", III, p. 50, has given the first more 

 detailed and in several regards good description of our plant. Of 

 his description I may here reprint the following: 



"Fronds at first globose, like tubers, heaped together, hollow 

 and empty or filled with seawater, attached to the rock and to 

 each other by a few short, rooting processes; at length irregularly 

 torn, and then forming expanded, cartilaginous, or skinlike coarsely 

 reticulated membranes. The membrane is wholly composed of a 

 single layer of large, globose, or by mutual compression hexagonal 

 cells, which closely cohere by their sides, leaving the convex ends 

 of cell free, and these form the surface of the membrane, which 

 when dry resembles a piece of fish skin, or a miniature honey- 

 comb. When the cells have been separated, each is seen to be 

 marked at the line of junction by a double row of circular discs. 

 In full grown cells the primordial utricle is easily separable from 

 the outer cell-wall, and contains a green, granular endochrome; 

 from which, by cell-division, four new cells are formed, and thus 

 the frond extends by repeated quadrisection of its component cells". 



This description shows that Harvey refers essentially to D. 

 favulosa but when he has "seen hairlike processes issue from it 

 (the cell-wall) internally" this shows that he has had to do with 

 another species also. 



J. A g ard h in "Till Algernes Systematik", VIII, p. 113 gives 

 a long discussion of Dictyosphœria but he does not carry us much 

 farther than Harvey, as also pointed out by Murray. 



In 1888 Askenasy in "Forschungsreise S. M. S. «Gazelle»", 

 IV. Theil, Botanik, p. 8 gives a rather detailed description of Dic- 

 tyosphœria favulosa. According to Askenasy the plant consists 

 of rather large cells which join each other by plane walls, except 

 at their upper and lower-most part where they leave open a small 

 space, this being in transverse section cuneate and filled with 

 small cells. Askenasy also discusses the cell-division: "Man findet 

 aber auch hier und da solche Zellen von mehr kugliger Gestalt, 

 die bis zu 5 mm Durchmesser besitzen. In diesen letzteren erfolgt 

 die Theilung des Inhaltes und die Ausbildung neuer Zellen, was 

 ich ganz sicher ermitteln konnte, da ich am Rande eines Thallus 

 eine Reihe solcher übermassig grossen Zellen antraf, von denen 

 einige noch ungetheilt, andere bereits getheilt waren (vgl. Taf. II, 

 fig. â). Bei der Theilung zerfällt die Zellen in zwei bis drei Schich- 

 ten übereinander liegenden Zellen, die genau so gebaut sind wie 



