664 RISEN. 



EXPLANATION OF PLATE XXXVL 

 Amphiuma mcsans. 



Fig. 22. An erythrocyte or red blood-cell. Zeiss D., Oc. 4. A large central 

 nucleus and four separate groups of centrosomes situated at the poles. These 

 groups are of about the same size, and equidistant. 



Fig. 23. Another erythrocyte, in which the four groups of centrosomes are less 

 equal in size, and not as regularly distributed; still each group is quite distinct. 

 This and the former figure represent the most common class of red corpuscles, in 

 which the centrosomes are situated far away from the nucleus and grouped at 

 the poles of the cells. 



Fig. 24. A red blood-corpuscle, or erythrocyte, belonging to a different class 

 from the last two. The cytoplasm in this class stains with basic stains. There 

 are no groups of centrosomes at the poles as in the former class, but close to the 

 nucleus is seen a pale, unstained zone, undoubtedly containing centrosomes and 

 spheres. These latter are only brought to view in the fusiform corpuscles. 



Fig. 25. A fusiform corpuscle derived from an erythrocyte, or red blood-cor- 

 puscle, of the class shown in Figs. 22 and 23. At the poles are seen centrosomes. 

 The nucleus is in strong degeneration, or dissolution. The hajmaglobin is already 

 diffused, and the outer membrane of the cell is breaking up. This class of fusi- 

 form corpuscles is entirely distinct from the following. 



Fig. 26. A fusiform corpuscle of the other type, derived from a red corpuscle 

 of the kind shown in Fig. 24. The nucleus is degenerated, but not to such a 

 degree as the one represented in Fig. 25. At each pole is seen a zone with differ- 

 entiated spheres and centrosomes, corresponding to the plasmocytoblasts of the 

 fusiform corpuscles of Batrachoscps. In this instance, however, they do not 

 develop into plasmocytes. The paler outer zone corresponds to the plasmosphere 

 and hyalosphere in the plasmocytes. 



Fig. 27. Two groups of centrosomes from a pole of a red blood-corpuscle of 

 Amphiuma. One or more centrosomes are seen to be surrounded by a proto- 

 plasmic envelop, which probably can be considered homologous to a somosphere. 



Fig. 28. Another group of centrosomes with somospheres. In many of the 

 smaller somospheres no centrosomes are visible. The group appears to be in 

 active division and development. 



