2 9 o SCIENCE PROGRESS 



preliminary account of an interesting new Zygopteris of an 

 early age, both at the Manchester meeting of the British 

 Association ; and by N. Bancroft's detailed and well-illustrated 

 work on the anatomy of Rachiopteris cylindrica Will. (Ann. 

 Bot. vol. xxix.). 



The presence of foreign pollen in fossil seeds is discussed by 

 Prof. F. W. Oliver (N.Phytologist, vol. xiv.) and the conclusion 

 reached that on the whole the pollen in a petrified seed is that 

 of the corresponding microsporangia. 



The year 191 5 is surprisingly rich in handsomely produced, 

 comprehensive, and important monographs which consolidate 

 known data and contribute many new facts to the science of 

 Paleobotany. No outstanding new theory appears to have 

 been advanced. An interesting feature of the year's output 

 is the relatively large number of papers from Russia, which 

 in the last few years has become an active centre of palaeo- 

 botanical work. 



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

 London. 



Protozoa. — An interesting account of the " General Biology of 

 the Protozoan Life Cycle " is furnished by Calkins (Amer. Nat. 

 May 1916). Experiments appear to show a gradual chemical 

 differentiation of the protoplasm with age. This senility may 

 be overcome by nuclear reorganisation, conjugation, encystment 

 and even cell division. " The Structure and Development of a 

 Myxosporidian Parasite of the Squeteague Cynoxion regalis " 

 is described by Davis (Jour. Morph. vol. xxvii. 1916). The 

 parasite, Sphcerospora dimorpha, is abundant in the urinary 

 bladder, and has two forms : one is disporous, and the other 

 polysporous. The spores are apparently the same in each case. 

 As is well known, the alimentary canals of goats and sheep have 

 a rich protozoan fauna, some of which pass through it in a 

 resting, encysted condition, undergoing their active phases in 

 moist dung. These forms are dealt with at length by Woodcock 

 (Phil. Trans. Roy. Soc. vol. ccvii. B) in " Observations on 

 Coprozoic Flagellates ; together with a suggestion as to the Signi- 

 ficance of the Kinetonucleus in the Binucleata." It is pointed 

 out that there is a close relation between the binucleate condi- 

 tion and the absence of syngamy. Incidentally too the author 



