1897.] Embryology. 637 
tial parts of spermatozoa and showed that these threads might well be 
the very large sperms of Amblystoma, seen and measured by S&S. F. 
Clarke. These masses thus agree essentially with the spermatophores 
of other tailless amphibia; they are more slender and higher than those 
of Diemyctylus, but built on the same general plan, and much less 
complex in form than those of the European triton. 
Though it is most probable that these bodies are the spermatophores 
deposited by the male Amblystoma before the female lays the eggs, yet 
it is, perhaps, possible that they may yet prove to be but preliminary 
attempts at egg laying; the female depositing some sperm within such 
secretion as is normally formed about the eggs. But this latter as- 
sumption seems scarcely tenable. 
We may conclude: (1). Fertilization in Amblystoma punctatum is 
internal (at least in the case observed). (2). Sperm-containing masses 
are often deposited before the eggs are laid; these are probably sperm- 
atophores put down by the male. (3). We may infer that the female 
gathers up the sperm from some of the spermatophores and that through 
this act the eggs are fertilized —E. A. ANDREWS. 
Cell Division and Nuclear Division.—Boveri® has repeated 
his notable attempts to fertilize non-nucleated pieces of the eggs of one 
species of sea-urchin (Echinus tuberculatus) with the sperm of another 
(Strongylocentrotus lividus) and finds incidentally some remarkable 
illustrations of the independence of nucleus and centrosome, and of the 
connection between the nucleus and cell division. 
In most cases where only one sperm enters such a non-nucleated 
piece of egg of another species the first cell division results in forming 
two masses—one with all the nuclear matter of the sperm the other with 
one centrosome and no nuclear matter. The mass with the nucleus 
continues to divide and forms a small blastula that may live three days. 
The other does not divide but remains as a single mass adjacent to 
the dividing cell; inside it, however, the centrosome does divide and 
with the same rhythm as in the first mass, so that there are ultimately 
a large number of centrosomes and stars in a single cell or non-nucleated, 
undivided mass. 
In fact the centrosomes go through all the phases they would in cell 
division, though the nucleus is absent ! 
Various facts and considerations lead the author to think it likely 
that the mitotic phenomena are started by conditions of the protoplasm 
that affect both the centrosome and the nucleus and lead them to go 
through their characteristic changes, independently of one another. 
è Ph. Med. Verein, Wurzburg. Oct., 1896. 
