1873.] On the Land-Planarians of Ceylon. 169 



It is shown that various names, both earth-connected and isolated, 

 have an exceedingly great power of discharging both kinds of electricity. 



The effects in regard to discharge are shown to be similar when plati- 

 num wire, rendered hot by a galvanic current, is used, and also when the 

 condensed electricity of a Leyden jar is experimented on. 



As hot iron shows a preferential power of discharging — over + 

 electricity, so it is found that white-hot but isolated iron refuses to be 

 charged either with + or — electricity. As the iron cools, it acquires 

 first the power of receiving — and afterwards of receiving + . Further, 

 while white-hot iron in contact with an electrified body prevents that 

 body from retaining a charge of either kind of electricity, as it cools it 

 permits a + charge to be received, and subsequently a — one. 



A suggestion is made as to the existence of an electrical coercitive 

 force, the presence of which together with its chminution by heat would 

 explain much of what has been described. 



February 20, 1873. 



Rear-Admiral RICHARDS, C.B., Vice-President, in the Chair. 



The following communications were read : — 



I. " On the Anatomy and Histology of the Land-Planarians of 

 Ceylon, with some Account of their Habits, and a Description 

 of two new Species, and with Notes on the Anatomy of some 

 European Aquatic Species/" By H. N. Moseley, M.A., 

 Exeter College, Oxford. Communicated by Gr. Rolleston, 

 M.D., Linacre Professor of Anatomy and Physiology in the 

 University of Oxford. Received January 16, 1873. 



(Abstract.) 



The writer commences by expressing his great obligations to Professor 

 Rolleston, whose pupil he formerly was. Professor Rolleston first in- 

 formed him of the existence of Land-Planarians in Ceylon, and of the 

 importance of investigating them. The paper was at first intended to be 

 a joint one, and Professor Rolleston himself made a number of prepara- 

 tions of Rhyncliodemus, one of which is figured. He likewise rendered 

 great aid in the bibliography, and by constant suggestions and assistance 

 during the progress of the work. 



Two new species of Land-Planarians from Ceylon are described, — one 

 belonging to the genus Bipalium (Stimpson), B. Ceres, the other to that 

 of Rhyncliodemus, R. Thwaitesii, so called after Mr. Gr. H. K. Thwaites, 

 E.R.S., the illustrious curator of the Peradeniya Gardens, by whose 

 assistance the specimens made use of were procured. 



