No. 404.] REVIEWS OF RECENT LITERATURE. 671 
to appear. The fore and hind limbs suffer rotation, so that the 
resultant upper surface of either is homologous with the lower sur- 
face of the other, as in Ceratodus. Pulmonary breathing begins 
before the external gills show signs of degeneration. About six 
weeks after hatching, the external gills are lost. The young Lepido- 
siren is remarkably newt-like in its general appearance and uses its 
hind limbs in, clambering about the vegetation. It also has some 
powers of change of color by the action of its chromatophores. p. 
Multiplication of Nuclei in Transversely Striped Muscle Fibres 
of Vertebrates. — Godelewski’s work, of which he gives a prelimi- 
nary account, was carried on at the Anatomical Institute of the Jagel- 
lonian University at Krakow. The material was from late embryos 
and recently born young ot the guinea pig and mouse, and from 
larve of Salamandra. ‘To avoid undue contraction of the muscles 
the whole extremity was employed; it was fixed in Perenyi’s fluid or 
in concentrated sublimate solution plus 2 per cent acetic acid. The 
sections, 5 4 thick, were stained either in thionin or in Heiden- 
hain's iron-hzematoxylin, followed by Bordeaux R or eosin. 
In the quiescent nuclei of embryonic or larval muscle cells the 
chromatin constitutes a thin layer at the periphery of the nucleus, 
which contrasts sharply by its blue color with the single brilliant red 
nucleolus. That the nuclei are highly elastic is shown by the flat- 
tened forms they assume in muscles that have strongly contracted 
owing to their being cut away from their attachments to bone before 
fixing. 
Nuclear reproduction takes place both by the mitotic and by the 
amitotic process. The author has observed all stages of mitosis in 
muscle fibres that were already distinctly striped, not only in the deep 
nuclei, but also in those that had already attained a peripheral posi- 
tion. The approaching division is indicated by an increase both in 
the size of the nucleus and in the distinctness of the chromatic net- 
work. The nucleolus disappears. The fibrilla next the nucleus 
Separate a little from each other, and a clear fluid plasma accumu- 
lates around the nucleus. If this is a marginal nucleus, it protrudes 
with its enveloping plasma beyond the surface of the fibre. 
Special attention was directed to the question of the presence of 
centrosomes. Though previous observers have never announced the 
existence of centrosomes in differentiated transversely striped muscle 
* Godelewski, E., Jr. Ueber die Vermehrung in den quergestreiften Muskel- 
fasern der Wirbelthiere, Bull. de l Acad. des Sciences de Cracovie. Avril, 1 
