Miscellaneous. 429 



as has hitherto been known only among the lower plants. And as 

 m them the conjugation has, as 'its end, the development of propaga- 

 tion-cells, so the conjugated Diporpce as a Diplozoon, develope gene- 

 rative organs and produce ova, which as simple Biporpa they were 

 not in the condition to do. ^t^ • 7 



It only remains to trace the development of the ova of i) iplozoon 

 into Diporpce ; but the researches which Prof. v. Siebold instituted 

 upon this point were unfortunately interrupted. 



In the same paper is contained a very interesting observation of 

 Dr. Fred. Cohn on the conjugation of Actinophrys, Sol., which was 

 first observed by KoUiker. 



Two Actinophrys approximate by means of their long rays, and 

 develope vesicular processes which become fused together. 



Between two such united animals a peculiar vesicle is frequently 

 seen, which contains a nucleus-like mass. 



Furthermore, a cellseform body of this kind was observed, sur- 

 rounded by a globular mass, which was plainly the body of an Actin- 

 ophrys, but had no rays. 



Prof. Siebold remarks, in conclusion, " I am persuaded that we 

 shall obtain surprising results from observations upon the copulative 

 process of the Protozoa, and we shall discover that different forms 

 will have to be regarded as generations belonging to the same species 



following one another in a fixed order." 



Here is a field wide enough for any one ; and it is much to be 

 wished that a tithe of the energy and perseverance displayed by 

 Enghsh microscopists in hunting after new species, could be turned 

 to such observation upon the vital processes of forms already de- 

 scribed. We should have fewer names and more knowledge.— -T. H. 



On a Leech new to the British Fauna. By J. E. Gray, Esa., F.R.S. 



Mr. Hoffmann lately sent to the Zoological Gardens a hving spe- 

 cimen of a very large leech which he had found near his house in 

 the Regent's Park. It has been preserved in fluid, and now forms 

 part of the Collection of British Animals in the British Museum. 



It proved to be an adult specimen of Trochetia subviridis, Dutro- 

 chet {Lamk. Hist. A. s. F. v. 523), well-figured in the 2nd edition 

 of Moquin-Tandon's ' Monograph of Hirudines,' t. 4. It is a very 

 interesting addition to the fauna. It is the giant of the family, this 

 specimen being more than 7 inches long.— from the Proceedings of 

 the Zoological Society. 



Government Manufacture and Publication of School-books and 

 Elementary Works of Science. 



We would direct the attention of our readers to the correspondence 

 between Lord John Russell and Messrs. Longman & Co. and Mr. 

 Murray, as recently published by them, copies of which we append 

 to our present Number. 



The attempt to estabUsh, under the patronage of Government, a 



