ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
293 
eventually come together and form a firm aggregate out of a scattered 
collection of isolated cells. Beside the change of position there is 
a marked change of form ; a cell may even divide while moving towards 
another cell. The author thinks that these movements are the result of 
chemical action, and it would appear to be clear that they are not simply 
physical, but results of life in the cells. They may be compared with 
those of sperm cells towards ova, and of conjugating Infusoria towards 
one another, and they may be all classed as cases of cytotropism. 
Zonula and Ora Serrata.* — Dr. W. Schoen finds that there is no 
ora serrata in the eyes of young children, for the line of transition to 
the retina is straight and without teeth. The macroscopic teeth, regarded 
as normal, are functional modifications acquired during life. The term 
ora serrata may be retained, but it primarily represents 600—800 micro- 
scopic processes, the origins of the zonula fibres ; the forty or so large 
teeth are secondary. A second deeper group of zonula fibres arises 
from the epithelial cells of the pars ciliaris. These zonula fibres are 
continuations of the membrana fenestrata and of the radial supporting 
fibres of the retina. The retina is continued not only in the ciliary 
epithelium, but in the whole system of supporting fibres which extends 
to the angle of the ciliary body and is attached to the capsule of 
the lens. 
Endings of Secretory Nerves.j — Professor C. Arnstein has investi- 
gated these in the pancreas, the salivary glands, and in the Harderian 
gland of rabbit, cat, and the like. He has also instigated Herr 
Dmitrewsky to do the same for the mammary glands, Herr Ostroumow 
for the skin-glands, Herr Timofeew for the prostate. 
In tubular or acinous glands alike, the nerves form a web on the 
membrana propria, and from this web circumcellular threads pass to the 
glandular cells. But they form no plexus nor network, but end in 
a definite terminal structure, often like a bunch of grapes or like a 
tendril with varicosities. The structure arises by budding and by 
secondary connections of varicose threads. Various forms may be seen 
on one cell. 
Intercellular Bridges of Smooth Muscle.* — Herr H. Boheman 
finds that the smooth muscle-cells in the alimentary canal of cat, dog, pig, 
and rabbit are connected by intercellular bridges. These are not, as 
Barfurth described, low ridges in the longitudinal direction of the cells, 
but consist of fine strands, which extend either for a short distance 
from one cell to its nearest neighbours, or for a long distance uniting 
more distant cells. The muscle-cells, like the epithelial cells of the rete 
I Malpighii, are surrounded by fluid-containing spaces, which are in direct 
connection with the lymph courses in the musculature. No cementing 
substance between the cells was demonstrable. 
Centrosome and Attraction-Sphere in the Resting Cell.§ — Dr. B. 
Rawitz finds that the resting cell of the Salamander’s testis is a bilaterally 
symmetrical element, with a regulating central “ organ,” namely the 
* Anat. Anzeig., x. (1895) pp. 360-4 (5 figs.). 
t Tom. cit., pp. 410-9 (12 figs.). t Tom. cit., pp. 305-15 (6 figs.). 
§ Arch. f. Mikr. Anat., xliv. (1895) pp. 555-79 (1 pi.). 
