i6o NATURAL SCIENCE. Feb., 1893. 



several of the best foreign Diatomists, who Hkewise failed to refer me to any 

 previous description. Mr. Hogg and Mr. Minchin dealt with generalities. I should 

 be glad to have a reference to any paper where these pseudopodia have been 

 described. 



Secondly, I have found these diatoms with the pseudopodia in almost every bit 

 of water — whether pond or stream — in the South of England, where I have looked 

 for them. They occur in many places in London and the suburbs, and from 

 Yarmouth to Sheerness, Eastbourne and Wiltshire. 



I advise my critics to take the trouble to get some of these diatoms and study 

 the phenomena for themselves. If they will do so, I do not think we shall hear 

 much more about either opinions, processes, or old discoveries. 



J. G. Grenfell. 



[I AM much surprised to find Mr. Grenfell including me among his " critics," 

 with regard to the pseudopodia of diatoms. I do not profess in any way to be an 

 authority on the subject, and the criticism which Mr. Grenfell kindly attributes to 

 me was quoted word for word from Mr. Jabez Hogg. It was Mr. Hogg, not I, who 

 asserted that the discovery of these so-called pseudopodia was a very old one, and 

 that they have often been described. Mr. Grenfell seems to have overlooked the 

 inverted commas in which these statements are placed. My only object was to place 

 before English readers an account of Professor Biitschli's researches upon the move- 

 ment of diatoms, and to point out that " any form of pseudopodia is quite inade- 

 quate and unnecessary to explain " the phenomena observed by him, without, 

 however, expressing any opinion of my own as to the existence or nature of these 



so-called pseudopodia. 



E. A. Minchin.] 



Pal-iontographical Society. 



The attention of the Council of the Palaeontographical Society having been 

 called to a paragraph in your January number, in which you wrote, " In the case 

 of several of these monographs, announced as in preparation, we believe the state- 

 ment is false, and that members of the Council are aware of the fact," I am directed 

 to state that all these monographs have been promised, and that the promises have 

 not been withdrawn. Thos. Wiltshire, Secretary. 



[Promises are fickle. We have already proved the accuracy of our assertion 

 in the case of two announcements, and the Secretary might be profitably " directed " 

 to make further enquiries. The continued official repetition of promises, which are 

 well known to be valueless, prevents other palaeontologists from undertaking works 

 that are much wanted. — Ed.] 



TO CORRESPONDENTS. 

 N.B.— CHANGE OF ADDRESS. 



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H. Ullvett (Folkestone). — The wingless bird referred to is not a species of 

 Apteryx, but the well-known Weka Rail [Ocydromus australis). Examples of this 

 common New Zealand Bird can generally be seen in the aviaries at the Zoological 

 Gardens in London. 



