340 



Mr. Karop thought it would be necessary to know some further particulars 

 before saying much about these specimens ; for instance — In what condition 

 were these diatoms when fonnd ? "Was the endochrome perfect ? because it 

 was not an uncommon thing for diatoms to get enclosed in other organisms 

 which devoured them, such as Vampyrella Vorax, which had a habit of so 

 doing. If this sort of thing took place the endochrome cells would break up. 

 Then it might be noted that many forms, such as Synedra, sprang from a 

 gelatinous mass, in which it was quite possible for other forms to get 

 enclosed. He thought, therefore, that this was probably a case either of 

 parasitism or of enclosure in the gelatinous portion of .another form, and 

 not what was generally known as encystment. 



Mr. Robinson, in reply to a question, said that he had not noticed if these 

 specimens occurred chiefly at any particular period of the year, but the 

 great number was remarkable, and rather puzzled him to account for on a 

 supposition that they had been devoured. 



Mr. Karop said that when Vampyrella went about it increased enormously, 

 so that the quantity of the diatoms need create no difficulty in the supposi- 

 tion that this was a case of parasitism. 



Mr. Goodwin thought it might be an early form of the diatom in which a 

 gelatinous envelope was found. When he saw the specimens he noticed 

 that they were seen in conjunction with the bundle of others in the same 

 cyst lying at right angles to them, and so far as he remembered they were 

 not fully grown. 



The thanks of the meeting were voted to Mr. Eobinson for his paper. 



Mr. E. M. Nelson gave a lengthened resume of the contents of his paper 

 " On the Interference of Light," which he said was intended as a popular 

 explanation of interference phenomena by presenting the ordinary 

 Fraunhofer formula in common language. He freely illustrated his remarks 

 by diagrams upon the blackboard. 



The President said he had listened to Mr. Nelson's paper with great 

 interest, but he feared the subject was one which must necessarily be treated 

 from a mathematical point of view, and that no one could grasp it without 

 some previous mathematical training. 



The thanks of the meeting were voted to Mr. Nelson for his paper. 



The Secretary announced the date and particulars of the whole day 

 excursion to "Whitstable as arranged for by the Excursion Committee. 



The proceedings closed with the usual conversazione, the following objects 

 being exhibited : — 



Plumatellarepens Mr. F. W. Andrew. 



Puparium of Hessian fly (Cecidomyia des-\ m • F F W 



tmctor) ... ... ... J 



Stained leaves Mr. F. H. P. Hind. 



Cyclosis in hair of Tradescantia virginica ... Mr. G. E. Mainland. 



Parasite from House fly Mr. C. Rousselet. 



Muscular fibre of Frog Mr. T. F. Smith. 



Attendance— Members, 45 ; Visitors, 2. 



