426 



The thanks of the Club were voted to Mr. Morland for his 

 communication. 



Mr. A. A, MerUn's " Note on the Tracheal Tubes of Insects, 

 etc.," was read by the Secretary. 



The President said it seemed rather remarkable that a thing 

 which had been known and studied for so long should have 

 remained until now before its true structure had been understood ; 

 and considering what had already been written by others upon 

 the subject, he thought it was just possible that in the case of 

 some insects the structure might be different from what it was 

 found to be in others. 



Mr. Hughes said that, hearing this subject was to be brought 

 before them, he had been looking up some old authorities on the 

 subject ; and, so far from the idea put forward in the paper they 

 had heai'd that evening being new, he found that Gosse, at least 

 forty years ago, was perfectly well aware of the facts which had 

 just been mentioned. On the other hand, however, Rymer Jones, 

 in his book on the Animal Kingdom, specially refers to the 

 tracheal structure, and says that the spiral fibre was continuous 

 throughout. 



Mr. Karop said a great deal had been written about this 

 structure, and from the examination of the trachea of Dytiscus 

 he was certainly of opinion that Mr. Merlin's view was correct. 

 He knew, however, the opposite opinion was held, and believed 

 that one man went so far as to say that he had unwound several 

 inches of the spiral fibre. 



Mr. Michael said he was not aware that this subject was 

 coming before them that evening, or he would have looked up the 

 references to it, but he was under the impression that it was not 

 by any means correct to say that it was generally accepted and 

 quoted in the text-books that the spiral was formed of a continu- 

 ous fibre. The non-continuous nature of the spiral structure 

 was not only recognised by some of the German w-riters on the 

 subject, but they also stated that it was not a fibre at all, but 

 only a thickening of the wall itself ; whilst others thought it was 

 not even that. He had noticed that amongst the Acarina the 

 spiral arrangement was common, but in the course of dissecting 

 some of the Oribatidse he found that though the spiral arrange- 

 ment could not be seen by any microscopic adjustment, it could 

 yet under certain circumstances be developed. In his book on 



