174 TKOCEEDINGS OF THE SOCIETY. 



resistant ego;s to hatch ; as a rale, however, the larger proportion fail to 

 respond to cooling. The addition of foul, contaminated fluid to the 

 receptacle in which such eggs are lying results in all or a very high 

 percentage of the dormant eggs liatching, frequently within five or 

 ten minutes. In collaboi'ation with Dr. E. E. Atkin, of the Lister 

 Institute, a considerable number of experiments in connexion with these 

 phenomena have been carried out. After sterilizing the eggs and 

 transferring them to tubes containing sterile fluids, it was found that 

 the eggs respond most readily to the introduction of living yeasts or 

 bacteria ; hatching .followed the introduction of a sterile autolized 

 extract of brewer's yeast. Killed cultures of bacteria and sterile watery 

 extract of brewer's yeast exerted a much feebler stimulus, and in the 

 case of strongly resistant eggs caused only a small percentage to hatch, 

 and in some instances failed entirely. In such cases the introduction 

 of the living yeast-cells or living cultures of bacteria (e.g. B. coil) never 

 failed to bring about the speedy hatching of the resistant eggs. Sterile 

 filtrates of bacteria were less effective than killed cultures. 



The addition of sufficient dilute acid to cause the same or a 

 somewhat stronger colour reaction than did a bacterial culture which 

 caused the eggs to hatch was ineffective. The addition of alkaline 

 solutions was either without effect or caused only a small percentage of 

 larvae to emerge, whereas when a little of a bacterial culture was added 

 to the containers the eggs which failed to respond to the alkaline 

 solutions hatched in large numbers within a few minutes. 



The most reasonable explanation of the phenomena would seem to 

 he the stimulus by smell, or some closely analogous sensation, of the 

 larva, followed by active use of its egg-breaking appliance. 



On the motion of the President a cordial vote of thanks was accorded 

 to Mr. Bacot for his exhibit and demonstration. 



On the invitation of the President, Professor Hickson, P.R.S., 

 then delivered an address on " Some Sedentary Foramiuifera," in which 

 he said that the small round red disks frequently found attached to dead 

 shells, to the base of corals, or to marine weeds of the semi-tropical and 

 tropical seas of the world had until recent years been usually referred 

 to the same species of Foramiuifera known as Polytrema miniaceum. 

 When these disks were captured alive and carefully preserved they were 

 frequently found to be the bases of small knobbed or branching coral- 

 like growths from 10-20 mm. in height, showing a very great range of 

 variability. The accounts given by Max Schultze and Carpenter of the 

 structure of Polytrema were so different from each other that it is quite 

 evident that they are descriptions of two different species of Foramiuifera. 

 Nevertheless, Schultze stated in a subsequent paper that he had examined 

 Carpenter's specimens and had come to the conclusion that they should 

 be referred to the one species, P. miniaceum. The lecturer showed that 

 the description given by Schultze applied to specimens of P. miniaceum 

 from the Mediterranean Sea, but the description given by Carpenter 

 applied to specimens of a sedentary Foramiuifera, to whicii he (Professsor 



