490 r. ERNEST WEISS. 



Amphioxus. I found it most expedient to leave the Am- 

 phioxi in water thickly clouded with carmine^ through which 

 a constant current of air was passed. As a further precaution 

 I changed the whole of the water every day, adding fresh car- 

 mine as before. In this way I was able to keep the Ampliioxi 

 for weeks together, and they seemed to remain as healthy as 

 those kept in running water. The current of air which was 

 passed through the water had the secondary but useful action 

 of preventing the carmine granules from settling down, and 

 this ensured a constant inhalation by the Amphioxi of carmine- 

 laden water. Such a current seems to have no irritating 

 action on these animals. I have been able by the aid of a 

 syringe to pass sea water very highly charged with carmine 

 through individuals, which were at the time in quite clear 

 water, without their seeming to notice it, certainly without 

 their closing their mouth for an instant, which they do imme- 

 diately anything obnoxious to them is brought into their 

 neighbourhood. 



After a day or two the Amphioxi will have taken up a con- 

 siderable amount of carmine in its very finest granules into 

 the cells of the intestine, and their faeces are made up almost 

 entirely of the coarser granules which could not be incepted 

 by the cells. 



From the intestinal epithelium the carmine is passed into 

 the intestinal blood-vessels, which seem charged with corpus- 

 cles (lymph-cells ?). 



Amphioxi which are kept longer still in carmine take up a 

 considerable amount of it into their vascular system, so that I 

 was enabled to follow out some of the blood-vessels, which are 

 otherwise very difficult to make out. 



Tlie intestinal vessels join anteriorly to form a single vessel 

 (Pfortader of .Miiller [1]; Darmvene of Schneider [4] ), which, 

 as Professor Lankester rightly states, is continued into the 

 endostylar or cardiac subpharyngcal trunk, though Miiller 

 asserted that it ended at the commencement of the cjecum. 



In each gill bar, whether primary or secondary (tongue bar), 

 there are two blood-vessels, one running on the inner side of 



