36 THE MICROSCOPE. 
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Manton, the managing editor of THe Microscorr, the pollen was 
received and sectioned at the Microscope Laboratory. From these 
sections the writer has been able to study the structure with much 
satisfaction and profit. ; 
Those papillze which appear as low and rounded elevations on 
the extine surface (Fig. 1), arise from the intine and protrude 
their convex extremities through circular openings in the extine. 
The two coats are separated by a distinct interval bea IB0T 
inch in depth (Fig. 2). 
This space is probably filled by a homogeneous fluid, as is pre- 
sumably the case with the clavate papille arising from the extine. 
I have been unable to see any granules between the membranes, or 
indeed any contents manifest themselves by optical characters. In 
sections (Fig. 2) the boundaries of both the extine and the intine 
are distinctly visible as extremely fine and delicate lines, showing 
that the membranes have an appreciable thickness, and that they are 
not in contact, and not connected by a solid intermedium. In Fig. 
2 is delineated a part of a section of a pollen grain, showing A the 
clavate hyaline papille, B the villous surface, D the extine, C the 
short papille rising from E the intine, while F represents the 
enclosed and coagulated protoplasm. The short papille originate 
by a somewhat broad base, followed by a constricted pedicle, ter- 
minating in an inflated free extremity which is rounded, yet some- 
what tapering to the summit. The height of each papilla is about 
=oo9 inch, including the thickness of the intine. Hach, therefore, 
projects about ;,';, inch beyond the external surface of the 
extine. The diameter at the point of exit through the external 
coat is about ;,';, inch. These measurements, however, are only 
averages, the distances varying somewhat in different grains. 
The pollen of the ‘‘moon flower” is an exception, therefore, to 
the rule that the extine bears all the markings and all the append-— 
ages. There are other exceptions in the Convolvulacez. 
In Fig. 4 is delineated an appearance seen in but one instance. 
Here the intine seems to have been partially torn away by the man- 
ipulation to which the pollen had been subjected, some of the small 
papillz having been drawn from and through the extine, leaving 
what appeared to be circular apertures with thickened margins. 
But that the reality was what it appeared to be, I am not ready to 
affirm. The aspect of the object was at least wonderfully suggestive. 
