PROCEEDINGS OF THE SOCIETY. 797 



to what had just been read, except that he was sure that the origination 

 of the varieties of Massilina secerns in the tank was due to the exhaustion 

 not merely of carbonate of lime, but of other chemical salts which would 

 lead to the abnormal formation of the shells. Ornament in the Foramini- 

 fera, when due to an exuberance or abundance of shell material, usually 

 took the form of spines or bosses. Whenever ornament took the form 

 of stride or sulci, he thought it pointed to exhaustion of material, as 

 borne oat by the remarks made in the paper. 



Mr. Maurice Blood said that the formation of striae, when shell- 

 forming material is scarce, is a remarkable example of adaptation in 

 such a lowly organism as a ribbed form of shell would be obviously 

 stronger than a smooth shell with a similiar amount of material. 



The Chairman concluded he. meant in addition to the spines. 



Mr. Blood said No, the converse. Striae were owing to lack of 

 material and tended to make a body stronger, in the same way that any 

 body of whatever shape made in ribbed form (as, for example, corrugated 

 iron") proved to be stronger than a smooth body of the same shape and 

 made in the same amount of material. 



The thanks of the Society were unanimously voted to Mr. Heron- 

 Allen and to Mr. Earland for their interesting paper. 



Mr. E. M. Nelson's paper, " A Micrometric Difficulty, 1 ' was read by 

 Mr. Scales. 



Mr. Nelson's paper, "On the Resolution of New Detail in a 

 CoscinoeUscus etsteromphalus" was read by Dr. Hebb, a blackboard 

 illustration being exhibited. 



The Chairman said that such papers as those which had just been 

 read were sometimes more difficult to follow than to read, and it 

 required an examination of the diatom in question to see whether 

 Mr. Nelson's remarks carried as much weight as might be gathered 

 from hearing his paper. He (the Chairman) knew the diatom mentioned 

 very well indeed, and he fully recognized that it was one thing to 

 discover new details, but quite a different matter to simply recognize 

 them after they had been discovered. He confessed that he had never 

 himself come across the markings described, but his attention had 

 never been drawn to them. It must be borne in mind, too, that the 

 discovery of new details in a diatom so well known and frequently used 

 might be due to using an objective whose correction just happened to 

 suit the object in question — hence the advantage in work of this kind 

 of employing objectives of similar focal length and aperture by different 

 makers. Testing objectives by diatoms only was not to be commended, 

 as he had pointed out elsewhere, save under special conditions. He 

 remembered an optician once telling him, " If you say what diatom you 

 wish to study, I will make you an objective specially for it." 



The thanks of the Meeting were voted unanimously to Mr. Nelson 

 for his papers. 



The Chairman announced that the Council wished him to state 

 that acknowledgments of the Addresses of Condolence sent by the 



