ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 95 



Chlorophyceas, and CyanophyceaE; ; the first and third including each only 

 one order, viz. Floridese and Schizosporese, while the Chlorophyceae are 

 again divided into four orders, Confervoideas, Siphonese, Protococcoideae, 

 and Zygospores). The author adopts Hansgirg's view with regard to 

 the polymorphism of algaa, and regards all our present systems of classi- 

 fication as only temporary. 



Lichenes. 



Gloeolichenes.* — Herr K. B. J. Forssell's monograph of this new 

 family of lichens is now published in detail. He defines the class as 

 Ascolichenes with gonidia belonging to the Chroococcaceaa. The 

 svmbiosis between the two constituents of the lichen may be indifferent, 

 antagonistic, or mutual. The algal constituent belongs to the genera 

 Chroococcus, Glceocapsa, and Xanthocapsa, possibly also to Aphanocapsa, 

 Glceothece, and Microcystis. The only kind of spore produced by the 

 fungal element is endogenous (ascospores) ; stylospores have not been 

 observed. The apothecia are either closed or open. The following 

 twelve genera are described in detail, with their species :— Cryptothele, 

 Pyrenopsis, Synalissa, Phylliscidium, Pyrenopsidium, Phylliscum, Gol- 

 lemopsidiuM, Enchylium, Psorotichia, Peccania, Anema, and Omphcdaria. 



Gasterolichenes. j — Mr. G. Massee describes under this name a new 

 section of lichens formed by the commensalism of a fungus belonging to 

 the order Trichogastres of Gasterolichenes, with a unicellular alga. 



The first example is the fungus known as Emericella variecolor Berk., 

 in which the algal constituent is Palmella botryoides. The cells of this 

 alga he describes as subglobose or broadly elliptical, varying from 

 20 to 39 /x in longest diameter, and furnished with a very thick lamel- 

 lose hyaline cell-wall. From the chlorophyllous portion of the cell a 

 green unseptated filament passes through the cell-wall, and is joined at 

 some distance to a similar filament from another cell, the two forming a 

 common stem, on which several pairs of cells are supported on similar 

 lateral bifurcating filaments. These pairs of cells originate from the 

 fission of a single cell. The alga occupies interspaces in the loose peri- 

 pheral portion of the base of the fungus, and also passes up into the loose 

 texture of the peridium. The tips of lateral branches of hyphse are 

 frequently seen closely investing and even penetrating the algal cells. 



A second type of Gasterolichenes is furnished by the fungus described 

 as Trichocoma paradoxa Jungh. Here the algal constituent belongs to 

 the genus Botryococcus, and forms a stratum at the base of the capillitium. 

 The colonies are generally invested with the hypha3 of the fungus. To 

 these Mr. Massee now adds a third hitherto undescribed species, 

 T. Isevispora. 



Action of Lichens on Rocks.J — Dr. J. Miiller makes an interesting 

 note on the weathering action of lichens upon rocks. Little excavations 

 containing the fructifications of lichens are often found on the surface 

 of rocks, especially limestones. Several species of Polyblastia have the 

 fructifications deeply buried, and it has been supposed that the lichen 

 gradually ate its way in by the aid of acid secretion. If this were true, 



* Nov. Act. R. Soc. Scient. Upsaln, xiii. (1887) pp. 1-118. See this Journal, 1886, 

 p. 485. t Phil. Trans., clxxviii. (1887) pp. 305-9 (1 p].). 



X Arch. Sci. Phys. et Nat., xviii. (1887) pp. 490-1. Bull. Soc. Murithicnne du 

 Valais, 1887. 



