202 



MEMORANDA. 



present Exhibition. In the foreign courts^ we must s^ay 

 that we have seen nothing, in many respects, to eompare 

 with their productions; but as our observations on these 

 have as yet been very superficial, we must reserve any 

 remark they may require to a future opportunity. 



Hints on the Mounting of Diatomaceae. — It is a matter of 

 importance to thos6 who are interested in the study of the 

 Diatomaceae, their distribution and habitats, that they should 

 be able to say, with some degree of certainty, that the speci- 

 mens contained on a given slide contain no mixture, but 

 really belong to the locality from which they are supposed 

 to be taken. These forms of life are, however, so minute, 

 that it is a matter of difficulty to wash either the test or 

 dipping-tubes so thoroughly as to free them entirely from the 

 diatoms remaining from previous examinations. The follow- 

 ing plan has been found simple, successful, and much less 

 troublesome than washing. Label the test- or dipping-tube 

 with the name of the deposit under examination, and never 

 use it for any other until it has been cleaned. To clean the 

 tubes it is only necessary to boil a number of them in a 

 strong solution of caustic potash, and then wash them in dis- 

 tilled water.— T. G. Stokes, M.A. 



The Collection of Microscopic Objects in the Norfolk Fens.— 

 I have received a number of applications for collections of 

 microscopical productions in the undrained fens of Norfolk 

 (see 'Journal' for April, No. vi, p. 117). The project has 

 been taken up much better than I could have expected, and I 

 now beg to thank all those gentlemen who have come for- 

 ward to assist me in my plans. The objects will consist of 

 Insecta, Characese, Algse, Diatomacese, Desmidaceaj, &c., 

 and dissections from the objects which so richly abound 

 in the undrained fens and surrounding sea-coast. A list of 

 the subscribers, with all the objects to be supplied, will 

 be sent to each subscriber on the 1st of July ; and another 

 list of all the objects procured before the distribution in 

 November, when all the objects will be equally divided 

 among the subscribers, and each one's share sent to him 

 about the 10th of November. The list is not quite complete. 

 I shall be happy to answer any inquiry through the post on the 

 subject. I have bred the fly which attacked the leaves of man- 

 gold- wurzel in the summer of 1861. There are two distinct 



