79 



cockroach, and that a discussion took place upon the subject. In the course of 

 that discussion some differences of opinion were expressed, but all agreed that 

 the salivary glands were always found collapsed, and the investigations which 

 he had made to that time seemed to confirm the observations. Some weeks 

 ago, however, he had killed a cockroach, and upon dissecting the thorax a bright 

 clear bead of something came out, which he at once snipped off, and put under 

 the microscope, and found it to be composed of fluid containing salivary 

 corpuscles. He then operated upon the other side of the insect, and found that 

 the other sac was filled also with fluid of the same kind. He exhibited the 

 specimen which he had preserved in alcohol. 



Mr. W. Carr observed that the salivary sacs could always be found fully in- 

 flated if the animals were kept a few days without food and were supplied with 

 only a little water. They used this saliva for the purpose of moistening the 

 food, and after feeding there would be very little of it found in the glands. By 

 adopting the plan named, he had no difficulty in finding the sacs full, and had 

 kept them in this condition preserved in fluid. 



Mr. W. W. Jones believed that these observations were quite correct. 



The President thought that if these sacs were preserved in fluid, endosmosis 

 would take place to some extent. He enquired if Mr Carr could tell him what 

 was the nature of the fluid. 



Mr. Carr was unable to say ; but it was something thicker than water. 



The President explained that the difficulty of preserving them in fluid arose 

 from the fact that fluids of different densities could not usually be kept separate 

 from each other merely by an animal membrane. 



Dr. Moore read a paper " On Bucephalus Haimeanus, and another allied 

 organism." 



The President thought the subject was a most interesting one, and as on a 

 former occasion they were debarred from discussing it from want of time, he 

 hoped there would be nothing to prevent a discussion on the present one. As, 

 however, Mr. W. Fell Woods had prepared a paper on the same subject, he 

 would call upon him to read it, and the two papers could then be discussed 

 together. 



Mr. W. Fell Woods then read his paper " On the Eelation of Bucephalus to 

 the Cockle." 



The President said that having heard these two interesting papers, he should 

 be very glad to hear some further remarks upon the subject from gentlemen in 

 the room. He had seen a paper bearing upon the subject which was written by 

 Van Beneden, a Belgian naturalist who had given much attention to these 

 animals, and who there described a creature which he said was parasitic upon 

 the cockle, and which he called Mnestra parasites. He thought that this rather 

 added to the difficulty. He should like to ask Mr. Woods if he thought that 

 the existence of these organisms had any influence upon the diminished supply 

 of oysters in this country ? 



Mr. Woods, in reply, said that seeing it had never been found in the oyster 

 in England, he thought it could not have any such effect. It had been found in 

 oysters from the Mediterranean. 



Mr. Charles Stewart said he was not acquainted with Bucephalus, nor was he 

 very well acquainted with the Lamellibranchiata, but he had seen this 

 organism exhibited, and he certainly thought it some species allied to a 

 Trematoid worm, for the reason that in the earlier stages of all the Lamelli- 

 branchiata there is fourd a locomotive apparatus known as the Vcliga; it 



