434 
George Arnold 
outermost microtome section of such material, I have observed mime- 
rous and typical synapses, in fact in those very osmicated portions 
where, according to the autliors above cited, no synapsis is seen. 
Nor is the chromatin massed to the exterior side of the cells in 
the fashion described by Mc Cluxg and quoted above. On the con- 
trary, in this animal even in adjacent cells the chromatin is sometimes 
massed in eacli at quite different parts (with refereuce to the direction 
of the fixative) of the nucleus. 
If then we lind synapses in even the external layers of the tissue, 
and whicli first come into contact with the fixative, we are well justi- 
fied in assuming tliat the synapsis is not an artificial product, and 
in reference to the material uiuler discnssion, it does not seem logical 
to say the synapsis is unnatural, but due to a condition of the cells 
in that particular stage, which permits the fixative to bring about a 
contraction of the chromatin. 
Moreover, I have shown that in the spermatocytes I of Hydro- 
phüus piceus (Arnold ’08) tliere occurs a synapsis in which the con- 
traction is towards the centre and not as usual, to oue side of the 
nucleus. 
Appareutly a similar synapsis occurs in the oocytes of Daphnia 
pulex tigured by A. Kühn ( 08), where the chromatin contracts round 
a centrally placed nucleolus. 
If according to Meves and others the effect of the reageuts used 
is such that the chromatin and linin is strongly contracted to oue 
side, how are we to explain that in Daphnia and Hydrophilus, the 
contraction is to the centre of the nucleus? It is unlikely that the 
same reagent (Flemming e. g.) should give two such entirely different 
results. 
Stains and fixatives used. 
1 have used Flemming’s stroug fixative in preference to the others 
mentioucd above, but Zenker’s is very useful for showing the reti- 
cular nature of the cytoplasm in the oocytes. 
The material was immersed in Flemming’s solution for 6 to 
12 liours, and in Zenker for 4 to 6 hours. 
The stains chiefly used were, — 
1. A triple stain, Saffranine, — Methvlene-blue, — and 
Orange G. For this stain the sections are mordanted (on the slides) 
for tive minutes in a solution of Potassium Iodide and Todine (equal 
