The Lake and Brook Lampreys of New York 471 



and contains both red and white corpuscles. This blood coag- 

 ulates ver}^ quickl}', and the fibrin is composed of exceedingly 

 fine and also coarser filaments. If preparations of lamprey 

 and human fibrin filaments are compared (PI. VIII, fig. 44, 

 45), it will be seen that in both there are centers from which 

 these filaments seem to radiate, and that in the lamprey, while 

 there are coarse filaments, the ultimate net-work is almost in- 

 conceivably fine and that in order to define it well, homo- 

 geneous immersion objectives are necessary. On the other 

 hand the net work of filaments in human and other mamma- 

 lian fibrin is coarse. This condition has been found in all the 

 mammalian fibrin examined, while the fine network seems to 

 be characteristic of the cold-blooded animals. 



The time required for coagulation in the lamprey is short, 

 shorter than for mammalian blood but not nearly so short as for 

 amphibian blood (Gage '90). 



The hemaglobin of the lamprey is exceedingly difficult to 

 obtain in crystalline form. The only successful efforts so far 

 have been by using a considerable quantity of blood and add- 

 ing at the edge of the cover a small amount of a 10 per cent, 

 aqueous solution of pyrogallic acid. The cover is then sealed 

 and put in the light in a cool place. After several da}^s, in suc- 

 cessful preparations, crystals appear in beautiful rosettes with 

 frond-like rays radiating from the center. 



The Red and White Blood Corpuscles. — It is to the solid 

 constituents of the blood that the greatest interest attaches, 

 and especially to the red-corpuscles ; for " as the red blood- 

 corpuscles of the camelidse form an exception in the great 

 mammalian group in being oval instead of circular in outline, 

 and, according to Gulliver in not forming di.stinct rouleaux, 

 or rolls, so the red corpuscles of the lamprey eels form an ex- 

 ception in the great non-mammalian group of vertebrates 

 (birds, reptiles, and fishes) in being bi-C07icave and circular, 

 instead of oval and bi-convex, like those of all other animals 

 in this great group. The corpuscles also agree with those of 

 mammals in forming distinct rouleaux. This is most marked 

 in the brook lamprey and the larva. In the 9 mm. embryo 

 the corpuscles were often seen in rolls of three or four in the 



