235 



In No. 1 the general anatomico- physiological relations of the order 

 are for the first time established with scientific precision, and a series 

 of species are described accordingly. In No. 2 a very remarkable 

 deviation of the genus Dinophilus is described. No. 3 contains the 

 description of seventeen Rhabdoceles, which are all new with the 

 exception of Convoluta paradoxa. In No. 4 are described nine 

 species of Rhabdoceles from the Mediterranean, mostly from the 

 Bay of Naples, together with some other worms. No. 5 contains 

 the list and special description of twenty species, of which ten are 

 new, observed in the neighbourhood of Cracow. The anatomical 

 descriptions embrace almost all the principal genera : Vortex, Dero-> 

 stomum, Mesostomum, Prostomum. Nos. 6, 7, 8 contain researches 

 respecting Turbellaria dendrocoela. The author has described most 

 of the freshwater species existing in Germany, and some from Corfu. 



Professor Schmidt's investigations extend to eighty species of the 

 Turbellaria rhabdocoela, and dendrocoela, sixty-two of which were 

 discovered by himself. 



Since Quatrefages published his ' Memoire sur les Planaries,' 1847, 

 and Dalyell published his observations on various orders of Turbel* 

 larise ('The Powers of the Creator,' 1851, 1853), nothing has been 

 done either in France or England to improve the anatomical know- 

 ledge of this very attractive group. Professor Schmidt declares that 

 he will consider it a reward for his own labours if English zoologists 

 can be induced by means of this notice to turn their attention to the 

 Fauna to which it refers. 



The following notice of his researches has been furnished to the 

 Foreign Secretary by M. Schrauf. 



Determination of the Optical Constants of Crystallized Sub- 

 stances. (First and Second Series.) By ALBERT SCHRAUF 

 (Vienna). 



In the two hitherto published series of these investigations, the 

 data concerning the refractive and dispersive powers of twenty cry- 

 stallized substances are communicated. 



Being persuaded that crystallo-physics, more than any other 

 branch of physical science, is founded on quantitative calculation of 

 absolute exactitude, I contrived to obtain first incontestable facts 



