666 E/SEN. 



EXPLANATION OF PLATE XXXVIL 

 Necturus maculatus. 



Fig. 29. A red blood-cell, or erythrocyte, under a low magnification, showing 

 the groups of centrosomes at each pole. The following figures show either 

 entire groups of centrosomes more highly magnified, or isolated centrosomes with 

 somospheres. As will be seen in the red blood-cell of Necturus, there is only one 

 single group of centrosomes at each pole, while in the red blood-cells of Amphi- 

 urna there are generally two or more. 



Fig. 30. A group of centrosomes. Some of the isolated bodies I consider to 

 be centrosomes surrounded by a somosphere. The pale yellowish zone surround- 

 ing these bodies ui Figs. 27, 2S, 30, and 36 may be common cytoplasma, or per- 

 haps a centrosphere. In Fig. 30 it is seen to have a distinct foam structure. Each 

 one of the two upper globular somospheres contains two centrosomes. The one 

 to the left has sent out a bud, in which is seen a rather undefinable centrosome, 

 perhaps an offspring from one of the larger ones. 



Fig. 31. Another group of centrosomes. The large somospheres are rounded, 

 globular, oblong, or even ring-like. In most of them are darker bodies, which I 

 consider to be identical with the centrosomes of Heidenhain, or the centriols of 

 Boveri. In many somospheres no centrosomes are found. 



Fig. 32. A somosphere sending out two buds, one of which is globular, the 

 other oblong. The dark bodies are the centrosomes. Many of these are not well 

 defined in the drawings, not being very distinctly outlined on the preparations, 

 which probably was due to optical or other imperfections. 



Fig. 33. A whole group of centrosomes and somospheres from the pole of 

 one of the red blood-corpuscles. 



Fig. 34. Another group of somospheres and centrosomes more highly magni- 

 fied. Oc. iS. 



Fig. 35. A group of centrosomes, with somospheres from one of the poles of 

 a red blood-corpuscle. Some of the somospheres apparently possess no centro- 

 somes. Oc. 12. 



Fig. 36. a-h represents five whole groups of somospheres and centrosomes 

 from the poles of the red blood-corpuscles. Figs. e,/,g represent isolated somo- 

 spheres with darker stained centrosomes. In the other figures the yellow ground- 

 substance represents either pure cytoplasm or centrospheres. 



STAINS. 



Polychromes-methylen-blue, nach Unna. Dr. G. Griibler & Co., Leipzig. 



Eosin. James W. Queen & Co., Philadelphia, U.S.A. Already mixed and in 

 solution, composition unknown. 



Toluidhte blue, extra. Actien-Gesellschaft f. Anilin-fabrication, Berlin (66,711), 

 I per cent, watery solution, 10 per cent, alcohol. 



Metanil-yellow. Actien-Gesellschaft f. Anilin-fabrication, Berlin. 



All stains were supplied by C. C. Riedy, San Francisco, Cal. 



