ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 257 



their divergence. He regards the sheath as intended for the protection 

 of the young growing point, and therefore as corresponding in function 

 to the bud-scales of dicotyledons. The points of resemblance and differ- 

 ence between the leaf-sheath of Equisetum and of Casuarina are also 

 dwelt upon. In the Equisetacefe the firmness of the commissure is chiefly 

 dependent on the silicification of the epidermal layer of cells ; in 

 Casuarina, on the other hand, to the lignification of internal cells. 



Muscinese. 



Peristome of Mosses.* — M. Philibert continues his observations on 

 the peristome of mosses. In the first place he discusses the difierence 

 between the Nematodontese and the Arthrodonte^e, and then points out 

 certain transitions between these two groups. One of the Polytrichacese, 

 Polytrichum juniperinum, is then described in detail. If a transverse 

 section be made of one of the teeth of this moss, it will be found to be 

 of the form of an isosceles triangle ; cell-cavities may be distinguished 

 which are oval towards the middle of the tooth but lunar at the edges. 

 The author in conclusion states that the structure of the peristome in 

 the Polytrichaceai does not resemble either in plan or origin that of 

 any other family of mosses. Besides Daivsonla, which is evidently allied 

 to this family, it is only approached to a very slight extent by the 

 Tetraphidese (Georgiacese Lind.). 



Shining of Schistostega osmundacea.t — Dr. F. Noll describes the 

 peculiar optical phenomena belonging to this moss, but only to its pro- 

 tonemal condition, it which it often clothes dark clefts in rocks. The 

 protoneme consists not of cylindrical cells, but of a single layer of cells 

 of very peculiar form lying at right angles to the direction of the 

 incident light. Each cell is of elliptical form, with the longer diameter 

 at right angles to the incident light, and with a projection on the side 

 furthest removed from the light. In this protuberance lie a small 

 number of chlorophyll-grains and the nucleus, the rest of the cell being 

 occupied by a colourless highly concentrated cell-sap. Dr. Noll points 

 out that the effect of this peculiar structure is, on optical principles, to 

 concentrate the rays of light on the portion of the cell occupied by the 

 chlorophyll-grains, and thus to counteract the influence of the small 

 amount of natural illumination. The effect is to cause an apparent 

 radiation of light from patches of the protoneme as it grows on the 

 wall of the dark rock. 



New Hepatic8B.J — Among the plants collected by Sintenis in the 

 West Indies in 18b5-1887, Herr F. Stephani describes the following 

 unpublished species of HepaticEe. From Porto Eico : — Aneura digiti- 

 loba, A. virgata, A. ZolUngeri, A. SchwanecMi, Kantia portoricensis, 

 Taxilejeunea antillana, T. Eggersiana, Odontolejeimea Berteroana, 0. Breu- 

 telii, Microlejeunea ovifolia, Cololejeunea stylGsa, Pycnolejeunea Schwa- 

 necMi, G. Sintenisii, Lepidozia commutata, Micropterijgium portoricense, 

 M. Martlanum, Badula portoricensis, B. iectiloha. From S. Domingo 

 and Dominica, collected by Eggers : — Bazzania Krugiana, Eulejeunea 

 Urbajii, Baddia Eggersiana. 



* Eev. BryoL, xv. (1888) pp. 90-3. Cf. this Journal, 1888, p. 1000. 

 t Albeit. Bot. Inst. Wiirzburg, iii. (1888) pp. 477-88 (5 figs.). Cf. thii Journal, 

 1888, p. 774. 



t Hedwigia, xxvii. (1888) pp. 276-302 (4 pis.). 



