RECENT ADVANCES IN SCIENCE 579 



and the problem investigated was " Can heritably diverse lines 

 be recognised among the descendants of a single specimen of 

 Arcella dentata produced by vegetative reproduction ? " 'I here 

 appears to be a certain correlation between the two factors 

 chosen, since on the average those of larger diameter had more 

 spines, and the limits of variation were, in diameter 73-15° 

 microns, in the number of spines^ 7-17. The two main conclu- 

 sions arrived at are : " A large family of Arcella dentata, therefore, 

 derived from a single specimen by vegetative reproduction, 

 consists of a number of branches that are hereditarily diverse 

 with respect to diameter and spine number. These diverse 

 branches resemble the hereditarily diverse families that were 

 obtained by vegetative reproduction from different " wild ' 

 specimens. The formation of such hereditarily diverse branches 

 appears to be a true case of evolution that has been observed 

 in the laboratory, and that occurs in a similar way in nature. 

 Other papers include : 



Flather, " The Effects of some Glandular Extracts upon the Contractile 

 Vacuoles of Paramcecium caudatum " (Biol. Bull., vol. xxxvii, July 1919) ; 

 and Kasai and Kobayashi, " The Stomach Spirochete occurring in Mammals " 

 (Journ. Parasit., vol. vi, Sept. 1919). 



Invertebrata.—A continuation of the investigations on " The 

 Axial Gradients in Hydrozoa " has been recorded by Child in 

 "II, Susceptibility in Relation to Physiological Axes, Regions 

 of the Colony and Stages of Development in Certain Hydroids " 

 (Biol. Bull., vol. xxxvii, Aug. 191 9). The author finds a de- 

 creasing susceptibility to lethal concentrations of KNC and other 

 salts on passing from the tentacles downwards, or from the apex 

 of the colony towards the base. It is possible, however, to 

 reverse this susceptibility under laboratory conditions, and 

 it is found that these regions are more capable of acclimatisation 

 to certain ranges of lower concentrations. 



Other papers include : 



Krecker, " Circulation of the Coelomic Fluid in a Nematode " (Biol. Bull., 

 vol. xxxvii, Sept. 191 9) ; Moore, " The Effect of Adrenin upon the Rate of 

 Locomotion of Planaria and Toad Larvae " (ibid., Sept. 1919) ; Stunkard, 

 " On the Specific Identity of Heronimus chelydrcB MacCallum and Aorchis 

 'extensus Barker and Parsons " (Journ. Parasit., vol. vi, Sept. 1919) ; Yoshida, 

 " On the Migrating Course of Ascarid Larvae in the Body of the Host " (ibid.) ; 

 Ackert, " On the Life History of Davania tetragona (Molin), a Fowl Tape- 

 worm " (ibid.) ; Guberlet, " On the Life History of the Chicken Cestode, 

 Hymenolepis carioca (Magalhaes) " (ibid.) ; Nakagawa, " Further Notes on 

 the Study of the Human Lung Distome, Paragonimus westermani " (ibid.) ; 

 Goto, " Dissotrema Synonymous with Gyliauchen " (ibid.) ; Tannreuther, 

 " Studies on the Rotifer Asplanchna ebbesbornii, with Special Reference to the 



