RECENT ADVANCES IN SCIENCE 231 



Laurent, whose note on the subject is included in the 

 memoir. 



These signs that the interesting floras of the Southern Hemi- 

 sphere are at last being described in a modern manner, and 

 rendered available for comparison with the other contemporary 

 floras, will be welcomed by Palaeobotanists all the world over. 



Wilson, in the Geological Survey Divisional Report for 191 6, 

 Ottawa, gave lists of a number of Mesozoic and other plants 

 added to the Museum. The collections were mostly identified 

 by Knowlton. Berry had a short paper on the Mesozoic 

 flora of the Atlantic coastal plain {Bull. Torrey Bot. Club, 

 vol. xliv.). Berry also published four or five small papers on 

 the Tertiary ; in Torreya, vol. xvii., he showed that the 

 Pleistocene plants in Maine afforded evidence that the climate 

 was then not much different from what it is at present. 



Family Histories and Anatomy. — Last year under this 

 heading there was something to say about almost all of the 

 leading groups of plants, but this year there are only three 

 or four papers to be mentioned, so that the headings will not 

 be maintained. 



Algse are represented by M. F. Romanes' " Note on an 

 Algal Limestone from Angola " (Trans. Roy. Soc. Edin. vol. 

 li. p. 581), in which are described sections of an Albanian lime- 

 stone from Angola. The rock showed, when weathered, warty 

 knobs about 1 cm. in diameter, which make up the greater 

 part of the rock, and are cemented together by a fine cal- 

 careous paste. The alga forming these knobs had a concentric 

 form of growth round some such nucleus as an echinoid plate, 

 or part of a spine. Two genera were identified, the more 

 abundant being Girvanella Nich., the other a species of 

 Lithothamnion, Phil. Two new specific names, G. Minima and 

 L. Angolense, were proposed, but without exact diagnoses. 



The Pteridosperms are represented by a detailed descrip- 

 tive memoir on "The Heterangiums of the British Coal Mea- 

 sures " by Scott (Linn. Soc. Journ. Bot. vol. xliv.). In this 

 H. Shorense, sp. nov., H. minimum, sp. nov., were described in 

 detail from micro-sections, and Williamson's original species 

 were also described and critically compared. Dr. Scott con- 

 cluded that the various species can be grouped into two sub- 

 genera, one including the first of the new species, together 

 with Williamson's H. tiliaoides and H. Lomaxii, while the 



