256 Scientific Intelligence. 



illustrated by figures of flint implements of various forms from 

 the vicinity of Ealing. To these are added representations of 

 similar implements from other beds of like age, and also from 

 those now in use among existing men, as the Esquimaux, Aus- 

 tralians, Fuegians and others ; and the frontispiece represents, in 

 an ideal picture, the method of chipping the flint into arrow-heads 

 and other forms. 



6. On the Organization of the Fossil Plants of the Coal 

 Measures. Part XIII ; by W. C. Williamson, LL.D., F.R.S. 

 Philosophical Transactions of the Royal Society of London, vol. 

 clxxviii, 1887. — Nearly six years have elapsed since the appear- 

 ance in 1882 of the twelfth of this remarkable series of memoirs 

 which, prior to that date had been issued at the rate of one every 

 year since their commencement in 1871. The casual observer 

 might infer from this that the powers of the distinguished author 

 were failing, but when we learn what other work he has done 

 during this interval we cannot wonder that the special investiga- 

 tions which are recorded in these memoirs have been somewhat 

 interrupted. 



One would suppose that the preparation of his splendid Mono- 

 graph on the Morphology and Histology of Stigmaria ficoides, 

 published by the Palseontographical Society in 1887, might have 

 occupied the whole of this time, not to speak of his work for the 

 British Association, as president of the Geological Section and 

 on committees for the investigation of the Tertiary flora of the 

 north of Ireland and of that of the Halifax coal measures, which, 

 with his other collateral work aggregate a score or more of im- 

 portant contributions from his pen to the science of fossil plants 

 during the past five years. 



The present memoir deals with some new phases of his two 

 genera, Heterangium and Kaloxylon, which he established in Part 

 IV of this series in 1873. The most important fact now brought 

 out is that these plants, while possessing most of the points of 

 structure essential to ferns, have, nevertheless, at the proper 

 period of their gi*owth, a distinct exogenous zone with a cam- 

 bium layer separating the xylem from the phloem. Relative to 

 the systematic position of these remarkable plants he is only cer- 

 tain that they have no representatives among living plants. He 

 suggests the possibility of their being the generalized ancestors 

 of both ferns and cycads, and cites Stangeria with its fern-like 

 dichotomous nervation linking these two families of plants by 

 their foliage in a manner similar to that in which these extinct 

 forms link them by their internal structure. l. f. w. 



7. Catalogue of the Fossil Mammalia hi the JBritish Museum/ 

 by Richard Lydekker, F.G.S., part V, London, 1887. — This 

 Part finishes the Catalogue. It includes the group Tillodontia, 

 and the Orders Sirenia, Cetacea, Edentata, Marsupialia and Mono- 

 tremata, together with miscellaneous notices in a supplement. 

 The critical notes in this Catalogue give it very great value. 



8. The Geological Fvidences of Evolution ; by Ajstgelo Heil- 

 prin, Prof. Invert. Pal. and curator Acad. Nat. Sci. Philad., 



