INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 919 



prothallium seen from above, i. e. from the apex of the si^ore, has a 

 nearly equilateral triangular form with rounded angles alternating 

 with the lobes of the exospiire. The first wall is vertical, cutting off 

 one of these angles. This portion, which may be called the sterile 

 third, develops into the large-celled knob which is always found at 

 the base of the archegonial surface of the prothallium, and never 

 bears archegoiiia. The further cell-division and formation of the 

 archegonia is described in detail in the poper. In the majority of 

 cases the archegonia are formed only on the ventral surface of the 

 prothallium which bears the " lump " behind ; but sometimes extends 

 somewhat on both sides, and even reaches the dorsal surface. The 

 distinction between the dorsal and ventral surfaces is clearly not due, 

 as in ferns, to a difference in the illumination, but is inherent in 

 the prothallium. 



The original tripolar development of the prothallium appears to 

 present some analogy with that of Hymenophyllaceas, except that the 

 large spore-cavity is first of all divided off by a septum. The mode 

 of formation of the archegonia reminds one again of Selaginella, in 

 which the archegonia form three rows alternating with the lobes of 

 the exospore. In Salvinia there are only two rows ; the third side 

 remaining sterile, and forming the " lump." 



Mtiscinese. 



New Bryum.* — Mr. H. Boswell describes a Bryum gathered in 

 Teesdale, without flowers or fruit, the form and texture of the leaves, 

 however, appearing distinct and sufficient to render it well marked. 



The name — B. Oritjanum — was suggested by the peculiar odour, 

 and it is thus characterized: — 



" Stems elongated, about an inch or more, copiously radiculose 

 and forming dense soft tufts. Leaves ovate and ovato-lanceolate, 

 shortly pointed, scarcely acuminate, concave, nerved almost to the 

 apex, cells lej^todermous, oblong and nearly rectangular, margins 

 plane, slightly recurved when dry, formed of a single row of narrower 

 cells." — Shady old wall, Teesdale. 



In soft dense tufts, foliage full green, the young leaves at the 

 summit rosy-pink, the old foliage of former years and lower part deep 

 brown, stems and leaves matted with numerous radicles. Habit and 

 general aspect much as in B. harbutum Wils., or some forms of 

 B. oeneum from Norway — from the former it differs in the form of the 

 leaves, which are not piliferons-acuminate, in tlie nerve ceasing 

 below the aj)ex, in the form of the cells, and their very thin walls. 



Fungi. 

 Structure of Chaetomium.t — W. Zopf has investigated the struc- 

 ture and development of this genus of Sphaeriacete,! and contributes 

 the results to the ' Proceedings' of the Botanical Society of Branden- 

 burg. He regards all the species which have hitherto been described 

 as modifications of a single one— which he calls Chcetomium hostrychodes, 



* ' Naturalist,' v. (1879) p. 33. 



t See ' Hedwigia,' xviii. (1879) p. 91. 



J Placed, in Cooke's 'Handbook of British Fungi,' among the Perisporiacei. 



