ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 473 



nema), or sometimes uni- and sometimes pluri-cel hilar. 1. In the 

 thalloid hepatics, the Marchantiaceae can regenerate from thallus, ventral 

 scales, epidermis, and to some extent from the assimilatory tissue. The 

 Anthocerotaceas regenerate preferably at the vegetative summit. The 

 Ricciacea? at the apical pole of the thalline fragments, and preferably 

 on the lower face and on the median line. The anacrogynous Junger- 

 mannieae regenerate the nearer to their apical pole, the higher the 

 differentiation of their thallus ; and here also on the morphologically 

 lower side and the nerve by preference. 2. In the foliose hepatics, the 

 acrogynous Jungermanniese may regenerate from fragments of stem, 

 preferably on the median line of the lower surface, often in the axil of 

 the amphigastria {Bazzania, Kantia, Chiloscyphus, Lophocolea, etc.). 

 From leaves, if completely detached, they regenerate either over the 

 whole surface, or only at the base, or sometimes at the margin. From 

 detached perianths they regenerate chiefly at the base. Among organs 

 which produce propagula there are two groups: (1) leaves when 

 detached cease producing propagula, and put out regeneration-shoots at 

 the same points as normal leaves ; (2) organs bearing discoid pluri- 

 cellular propagula (Brutkuchen) do not cease forming them ; on the 

 contrary the propagula, which appear as warts on the leaves (Brutwarzen) 

 are transformed into shoots. Of the sexual organs, the antheridia 

 rapidly perish ; but the archegonia readily form shoots, preferably at 

 their base. Kreh has entirely failed to obtain any result from the 

 sporogonium and its stalk. The hepatica? thus have great powers of 

 regeneration, and in nature benefit much by them. When parts of the 

 plant are detached by insect agency, they sprout and serve as organs of 

 vegetative propagation. 



Some Irish Forms of Fissidens.* — H. N". Dixon gives an account 

 of Fissidens exsid, a new species from the palm-house in the Botanic 

 Gardens at Glasnevin. It is allied to F. tequendamense found near 

 Dublin in 1880 and published under the name of Schistophyllum Orrii, 

 and to Fissidens algarvicus, but differs in being larger, with more 

 numerous and larger leaves with chlorophyllose cells, and in its longer 

 seta. It differs from F. incurvm in leaf -apex, areolation, and peristome. 

 The inner face of the basal part of the peristome of F. exsul and of 

 F. algarvicus is adorned with a series of remarkable prominent lamelhe, 

 fringed at the margin with cilia. These fringed lamelhe are very 

 difficult to observe, owing to the fragility of the teeth when dry, and 

 to their strongly incurved position when wet. Dixon also describes a 

 new form of F. raftdus, from a quarry near Finglas Bridge. It is 

 characterised by great variability in the development of its leaf -border, 

 which may be partly or completely suppressed on the superior and 

 inferior larninas. 



Revision of the Species of Philonotis.f — A. Cornet gives a resume 

 of, and makes some remarks upon, Dismier's Essai Monograph ique sur 

 les Phttonotis de France .% Philonotis is a most polymorphic genus, in 

 which the species and their forms have been lamentably confused by 



* Journ. Bot., xlviii. (1910) pp. 145-9 (pi.). 



t Bull. Soc. Roy. Bot. Bclg., xlvi. (1909) pp. 307-9. 



\ Mem. Soc. Sci. Nat. Cherbourg, xxxvi. (1908) pp. 367-428. 



