ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 79 



istic internal xjlem is very well shown. The specimen evidently belongs 

 to the genus AnTcyropteris^ as also probably does Zygopteris scandens. 

 The author discusses the peripheral loops of the leaf -trace bundles, etc. 



Jurassic Plants of Yorkshire.* — H. Hamshaw Thomas gives a 

 summary of recent researches on the Jurassic plants of Yorshire, and 

 of the results obtained by Nathorst, T. G. Halle, and himself. He cites 

 Nathorst's discovery of the male sporophylls of Williamsonia (Bennetti- 

 tales) ; his discovery of a new bisexual Bennettitalian " flower " near 

 Gristhorpe, and of small fruit-like bodies of Caytonia ; Halle's descrip- 

 tion of pear-shaped sporangia with a cap of thickened apical cells in the 

 mesozoic fern GladophUbls denticulata. Also fertile specimens of C. 

 lohifolia have been found, recalling Dicksonia ; and of Coniopteris hymeno- 

 phyUoides, recalling Cyatheaceas ; and remains of Neocalamites and 

 Jlarattiopsis, both new records for Yorkshire. 



Formation of Calcareous Nodules containing Fossil Plants.f — ■ 

 T. Lockhart gives an account of the results obtained by cutting some 

 boulders of calciferous sandstone from Pettycur into thin serial sections, 

 and examining the latter successively for fossil plants, by way of deter- 

 mining accurately the actual position occupied by the plants in those 

 blocks. Metaclepsydrop)sis duplex and Botryopteris antiqua were thus 

 followed out. The effect of fractures and of water currents is rendered 

 obvious ; and Gordon's views of thermal pools as the actual site of 

 petrifaction are confirmed. 



Bryopliyta. 

 (By A. Gepp.) 



Homology of Antheridial and Archegonial Involucres in Liver- 

 worts. | — K. Goebel discusses the homology of the antheridial and 

 archegonial bracts of liverworts ; and publishes a description of a new 

 species, Fossombronia Lutzelhurgiana. In this latter the elaters are 

 very degenerated — a case parallel with what occurs in the Marchantiaceae, 

 and supporting the view that the sterile cells of Corsinia and RieJla are 

 arrested elaters. The author examines the question how far the invo- 

 lucres of the archegonia are homologous with those of the antheridia, 

 which in certain conditions are quite reduced. He attempts to prove 

 that the position of the antheridia and archegonia is a similar one. 

 Some small differences, it is true, occur in the gathering of the arche- 

 gonia into groups for faciHtating fertilization ; this may occur at the 

 apex of acrogynous Jungermanniaceae, and it is customary in the thallose 

 forms. Where the archegonium is solitary, that reduction has only been 

 made possible by unusually favourable conditions for fertilization. The 

 archegonial perianths are homologous to the antheridial involucres in both 

 thallose and foliose forms. The development of perianths (and indeed 

 partly their subsequent development, partly their first rudiment) is, how- 



* Rep. Brit. Assoc. Portsmouth, 1911 (1912) pp. 569-70. 

 t Rep. Brit. Assoc. Portsmouth, 1911 (1912) p. 570. 

 X Flora, V. (1912) pp. 53-70 (figs.). 



