642 SCIENCE PROGRESS 



and, further, the individuals show a similar numerical increase. 

 This additional flora comes in from the margins of the wood 

 and the rides, whither it is once more driven as the sprouting 

 stools again diminish the light. Another effect of coppicing, 

 important to the forester, is the increased acidity due to the 

 breakdown of humus and a consequently lowered water 

 capacity. 



Taxonomy. — An interesting abnormality has been encoun- 

 tered by Small {Annals of Botany, vol. xxx. pp. 19 1-2) in the 

 groundsel Senecio vulgaris, which is probably of phylogenetic 

 significance. In several instances the ovaries were found to 

 contain two ovules and in one case the ovary was bilocular. 

 In all the examples the ovules were attached parietally and there 

 was evidence that the series exhibited all four placentae of a 

 bicarpellary ovary. Such observations gain from the fact that 

 more than one ovule has been recorded in the ovaries of the 

 dandelion and species of zinnia. 



ZOOLOGY. By Chas. H. O'Donoghue, D.Sc, F.Z.S., University College, 

 London. 



Protozoa. — Mast and Root have made a series of " Observa- 

 tions on Amoeba fed on Rotifers, Nematodes, and Ciliates, and 

 their Bearing on the Surface-tension Theory " (Jour. Exper. 

 Zool. July 19 1 6). Amoeba cuts the paramcecium in two, and 

 this was done experimentally and the energy required calcu- 

 lated, from which they deduced the energy employed by the 

 amoeba. They conclude that surface tension of the proto- 

 plasm is at best an insignificant factor in the process of feeding. 

 In another series of " Observations on Ciliary Currents in Free- 

 swimming Paramcecia " (ibid. Aug. 191 6), Mast and Lashly 

 point out that there is no feeding cone while paramcecium is 

 swimming about but only while it is at rest. 



Invertebrata. — A new form of sponge spicule is dealt with 

 by Dendy in a note " On the Occurrence of Gelatinous Spicules 

 and their Mode of Origin in a new Genus of Siliceous Sponges " 

 (Proc. Roy. Soc. B, No. 616, 1916). They are termed " collo- 

 scleres " and as far as can be ascertained consist of colloidal 

 silica. 



Cary writes on " The Influence of the Marginal Sense Organs 

 on the Rate of Regeneration in Cassiopea Xamachana " (Jour. 

 Exper. Zool. July 1916), reaching the conclusion that regenera- 



