RECENT ADVANCES IN SCIENCE 43 



meteorites in a form which closely resembles the member of 

 the apatite group which has been termed francolite. E. T. 

 Wherry (Amer. Miner. 2, p. 119, 191 7), however, points out 

 that the mineral differs from francolite in optical properties, 

 and as it contains no fluorine, chlorine, carbon dioxide, etc., it 

 should be excluded from the apatite group and regarded as a 

 pure calcium phosphate. The same writer (ibid., pp. 80-81, 

 191 7) has measured a crystalline phosphide of iron which 

 occurs in Ruff's Mountain meteorite, and which is supposed 

 to be identical with the tetragonal phosphide of iron measured 

 recently by L. J. Spencer (Min. Mag. 17, pp. 340-43, 1916), 

 the angular values in the two cases being similar. 



BOTANY. By E. J. Salisbury, D.Sc, F.L.S., East London College, 

 University, London. 



Anatomy. — Kashyap (Annals of Botany, July and Oct. 191 7) 

 finds that there is a special endodermal sheath for each bundle 

 in the nodes of both stem and rhizome of Equisetum debile, 

 but that two distinct endodermal sheaths are present in the 

 internodes. Occasionally these two fuse around islands of 

 parenchyma. The prothalli of this species when crowded 

 are unisexual, but when growing isolated, become large and 

 at first bear archegonia and subsequently antheridia. 



In the same journal Maybrook describes the anatomy of 

 the haustoria of Pedicularis vulgaris, which apparently possess 

 no phloem. The place of this tissue is taken by elongated 

 parenchymatous cells, whilst the xylem tracheids contain 

 abundant protoplasm. 



The late Miss Holden describes two new species of Dadoxylon 

 under the names D. indicum and D. bengalense, both from the 

 Permo-Carboniferous rocks of India. The former has a large 

 non-discoid pith between which and the xylem proper is a 

 jacket of transfusion cells. The primary wood consists of 

 separate endarch bundles with a brood transition zone of 

 metaxylem. The two species agree in the possession of 

 distinct annual rings. 



Dr. Scott, as a result of his study of " The Heterangiums 

 of the British Coal Measures " (Journ. Linn. Soc. Bot., vol. 

 xliv.), suggests the establishment, on anatomical grounds, 

 of two sub-genera. The first of these, for which the name 



