Dr. Collingwood, on Microscopic Alga. 85 



for the purchase of slides, when such as we want may be had 

 by purchase. 



At the last year's anniversary our numerical strength was 

 390; in the session just closed the elections have numbered 

 seventy-four; we have lost four by death, and eight by 

 resignation. Our present strength is, therefore, 453 Fellows; 

 of these 361 are annual subscribers, and ninty-one com- 

 pounders. 



Thus the Society is flourishing, as viewed in respect to 

 finances, number of its Fellows, and increase in property. 



The last year has been one of great and unusual exaction 

 of time and work from all your officers, and particularly from 

 the secretaries, without whose zealous assistance I do not 

 know how all the work could have been done which has 

 been done, nor the library prepared for use ; I am greatly 

 myself indebted to them. 



In conclusion, I beg to offer my thanks for the courtesy 

 I have received from every member of every committee, and 

 from every member of the Council, and to you for the 

 support you have given me in performing the duties of your 

 President. 



Observations on the Microscopic Alga which causes the 

 Discoloration of the Sea in various parts of the 

 World. By Dr. C. Collingwood, M.A., F.L.S. 



(Read March 11th, 1S68.) 



Although a great deal has been written at various times 

 on the subject of the floating substance known to sailors as 

 sea sawdust, whale's food, &c., it does not necessarily follow 

 that there is not still much to be added by those who have 

 themselves observed the phenomenon. Moreover, although 

 travellers have from tigie to time recorded the appearance of 

 this substance upon the surface of the ocean in different parts 

 of the world, it so happens that those who have written the 

 most elaborate articles upon it have either never seen it (as, 

 for instance, Montague), or had but limited opportunities for 

 its observation, which latter was indeed the case with Ehren- 

 berg. Again, the interesting accounts written by these 

 naturalists have referred almost exclusively to the substance 

 produced in the Red Sea, and to which they attribute its 



