No. 3-] BLOOD-PLATES OF THE HUMAN BLOOD. 653 



latter is broader, with an even, smooth outHne. There is also 

 another important difference between the two cells. The 

 nucleus of the rounder cell generally possesses a slight depres- 

 sion at each pole, and adjacent to this is seen a narrow, differently 

 staining zone, which under certain favorable conditions resem- 

 bles the granosphere with centrosomes in the fusiform cor- 

 puscles. No such zone is found in the longer corpuscles. It 

 appears, therefore, as if the groups of globules in the longer 

 corpuscles are morphologically of the same nature as the cen- 

 trosomal spheres in the round corpuscles. 



As might be expected, we also find in the blood of these 

 species two distinct kinds of fusiform corpuscles. One kind 

 (PI. XXXVI, Fig. 25) is undoubtedly a degenerated oblong red 

 corpuscle, retaining all its characteristics. The nucleus is in 

 a far advanced state of degeneration, while the groups of glob- 

 ules and granules are yet in position at the poles. The other 

 kind of fusiform corpuscle is shorter. The nucleus possesses 

 a depression at each pole, and outside of this we find the 

 cytospheres, granosphere, centrosphere, and centrosomes, more 

 or less distinctly brought out. These latter structures corre- 

 spond to the plasmocytoblasts in the blood of Batrachoscps. In 

 the blood of Necturus and Ampliumia they do not develop into 

 plasmocytes. 



XIII. Structure of the Oblong Erythrocytes. 



The oblong red corpuscles of both Ampliiiima and Necturus 

 are so similar that in the following pages I shall refer to them 

 together, after first having mentioned the difference between 

 them. Even with a comparatively low power it will be seen 

 that at each pole, outside of the nucleus, there exist one or 

 more groups of dark-staining granules. In Necturus there is 

 generally only one such group at each pole, while in Amphiuma 

 there are several, nearly always arranged in pairs of two, four, 

 or six, at or near the pole. Occasionally we find smaller 

 groups at the sides, or even isolated globules. In Figs. 22 and 

 23 I have figured two erythrocytes from Amphiuma, and in 

 Fig. 29 one from Necturus ; both under a moderate power 



