654 EISEN. [Vol. XV. 



of magnification. In Necttcrtis the groups are always smaller 

 than in Amphiuma, but otherwise there is a great resemblance 

 between them. 



Under the highest systems these groups resolve themselves 

 into a number of small globules of different sizes and shapes ; 

 and in the majority of globules we find one or more small, dark 

 granules. The appearance of these globules and their darker 

 granules is such that I can only compare them to centrosomes 

 surrounded by a differentiated and differently staining sphere. 

 As to the nature of this sphere I am somewhat undecided, but 

 from analogy am inclined to consider it identical with the somo- 

 sphere, previously described (Eisen, p. 17, etc.). Especially in 

 Necturiis is it readily demonstrated that these globules are sur- 

 rounded by or connected by a very thin, foam-like cytoplasm 

 of irregular form. Whether this is cytoplasm pure and simple, 

 or whether it partakes of the nature of archoplasm in the 

 sense of Boveri, is not to be determined at present, as the 

 haemoglobin in the cells evidently prevents a proper differ- 

 entiation. The somospheres and centrosomes are, however, 

 readily stainable, and a study of them is not connected with 

 difficulties, provided double staining is not attempted. Every 

 effort at double staining with eosin or with fuchsin mixtures 

 has proved a failure. With such stains these groups are not 

 even brought out, but remain unstained. They stain readily, 

 however, with basic aniline dyes, such as the methylen blues, 

 toluidines, thionins, gentian-violet, etc. I have found poly- 

 chromes-methylen-blue one of the best. With this latter stain 

 we find that the globules are not always as regular as they 

 appear to be at first. They are sometimes confluent, some- 

 times send out ramifications and projections, as, for instance, 

 in PI. XXXVI, Figs. 27, 28, etc. As a rule, we find one or 

 more dark granules in each such projection or globule, but in 

 many instances there are none to be seen. The globules may 

 be' more or less numerous in each group. In Necturus there 

 are seldom more than a dozen, while in Amphiuma I have 

 sometimes counted thirty in a group. The darker granules 

 appear to increase in number by budding in a manner similar 

 to that of centrosomes, as described by Heidenhain, and this 



