The Lake and Brook Lampreys of New York 463 



tioii. It may be farther stated that when the lamprey has 

 gorged itself with blood, the first marked change appearing 

 in the blood taken as food is the reduction of the oxy-hemo- 

 globin to hemoglobin. Without doubt the oxygen stored in 

 the hemoglobin by the respiratory activity of its prey is used 

 for respiratory purposes by the lamprey. As pointed out by 

 Bert ('70) and others, any thin and highly vascular membrane 

 may serve as a respiratory membrane. The alimentary canal 

 of the lamprey answers admirabl}^ these conditions, and on 

 opening the gorged intestine of a lamprey just taken from a 

 fish, one can trace with the eye alone the gradual transforma- 

 tion of the oxygenated blood through gradually darkening 

 shades until the blood is almost black. Examined with the 

 micro-spectroscope, the transformation can be followed with 

 great definiteness and by agitating the black blood with air it 

 reddens and the two characteristic bands of oxy- hemoglobin 

 reappear. No doubt this use of the oxygen obtained by 

 another fish is of considerable importance to the lamprey, and 

 there is realized by it very perfectly the obtaining of ordinary 

 and gaseous food at the same time. 



With the larva, the motions are very energetic for a short 

 time, then the animal lies on its side panting, as it were, the 

 respirations are so rapid. In nature, however, only very 

 rarely is great exertion necessary, as in burying itself in sand 

 after voluntarily or accidentally becoming free in the water, 

 also by moving through the sand for a more favorable locality. 

 Almost the only other muscular activity consists, not in mov- 

 ing the whole body, but in pumping water into and out of the 

 broncho-oesophageal chamber for the combined purpose of 

 respiration and obtaining food. 



Respiratory Mechanism and Movements in the Larva. — If a 

 larval lamprey is placed in a glass vessel with coarse sand and 

 a plentiful supply of water it will very soon make a suitable 

 burrow or canal in which to live. Very frequentlj^ the bur- 

 row will be made in part next to the glass, in which case one 

 may observe with great definiteness all the respiratory move- 

 ments, especially if a magnifier is used. It is seen that in re- 

 pose the respirations are not far from 100 per minute, sometimes 



