470 Simon Hefiry Gage 



While the branchial pouches are, as stated above, practi- 

 cally independent, nevertheless they do communicate through 

 the common bronchus, and occasionally a particle entering 

 the branchiopore of one side may be seen to emerge from the 

 opposite branchiopore (Bert, '67). If one observes the respira- 

 tion of a lamprey resting upon its side in very shallow water 

 so that the branchiopores are near the surface, the oblique 

 streams from the branchiopores are very readily seen. If the 

 nostril is near the surface of the water a stream is seen to 

 emerge from it at every expiration. Hence as the nasal sac 

 is closed caudally, a stream must be drawn in at every inspi- 

 ration and expelled at every expiration. This movement 

 simply accompanies respiration and is not for respiratory, but 

 rather for olfactory purposes. That there is no connection 

 between the stream forced from the nostril and the respiratory 

 water may be easily proved by raising the head slightly above 

 the water. After the first expiration no further jets of water 

 are sent from the nostril until the head is again submerged, 

 thus showing that the water enters and emerges from the 

 same opening. 



All the respiratory movements may be artificially imitated 

 on a lamprey soon after death, if the branchial apparatus 

 remains expanded. To insure this the lamprey may be cura- 

 rized ; the branchial apparatus being unconstricted by the 

 paralyzed muscles, expands by its own elasticity, and the 

 animal will die in the inspiratory phase. If now the branchial 

 apparatus is grasped by the hand the expiration may be im- 

 itated by constricting the apparatus and the streams from the 

 branchiopores and from the nostril demonstrated. Upon re- 

 laxing the grasp the branchial apparatus re-expands and re- 

 fills the gill pouches. By proceeding slowly, one can see 

 with the greatest accuracy the movement of the branchioporic 

 valves, and what is obscure, from the rapidity of action in the 

 living state, becomes clear and intelligible. 



THE BI^OOD AND ITS FIBRIN, HEMAGIyOBIN AND CORPUSCLES. 



As in the higher vertebrates, the blood of the lamprey in 

 all stages, except the very early embryonic ones is red in color 



