2 Transactions of the Royal Microscopical Society. 
less skill in micro-photography, Dr. Woodward replied ;* reaffirming 
his conviction that the “longitudinal strie of Dippel,’ and, in 
addition, those announced to have been seen by Mr. Hickie, were 
due to diffraction and interference; the spurious lines produced by 
which, he declared and proved, could be as readily photographed as 
real ones. Some beautiful photographs in support of this were 
sent ; and certainly to the skilled observer there can be no question 
that in the case of the frustules photographed by Dr. Woodward 
(and excellently reproduced in this Journal +) the lines photographed 
are spurious. Further, whoever has taken note of Dr. Wood- 
ward’s skill in manipulating test and other difficult objects, will 
want no assurance, that in reference to the frustules in the photo- 
graphs, if they could not be developed by Dr, Woodward, the 
probability is that they could not be developed at all. But this 
observer adds a note of extreme significance in this relation ; for he 
says, “ At the same time I shall be very glad if he (Mr. Hickie) 
can convince me, by satisfactory evidence, that this belief is 
erroneous, for analogy inclines me towards the opinion that in both 
Frustulia Saxonica and Amphiplewra pellucida the striz are 
really rows of beads, as is so easily to be seen in Navicula 
rhomboides, and that consequently we ought to be able to see 
longitudinal strize when the illuminating pencil has the proper 
direction, if only our glasses had the requisite defining power.” 
The italics are mine, but they show the sound and unbiassed view 
of the writer. 
A rejoinder is now given by Mr. Hickie.} In this occurs a 
letter from Dr. Rabenhorst, declaring the longitudinal striz of 
F, Saxonica to be real, and affirming that “if Dr. Woodward main- 
tains that Frustulia Saxonica is identical with Navicula eras- 
sinervis we must suppose that he is ignorant of one or other of 
them.” At the same time Herr Seibert’s photographs of the 
longitudinal as well as the transverse striz of a reputed “ #. Saa- 
onica” were presented to this Society for inspection. At the 
discussion which followed the reading of this paper it was affirmed 
that the photographs were simply indistinguishable from “ coarse 
Rhomboides,’ § and in both the paper and the discussion Mr. Hickie 
retracted “a previous erroneous statement,” and confessed that he 
was unable to ‘‘ state where Frustulia Saxonica ends and ‘ small’ 
Rhomboides begins.” || They were in fact identical. But he still 
maintained that ‘‘there was a very great difference between them 
and Crassinervis.” 4] 
After this, in a subsequent paper,** Dr. Woodward definitely 
proved that Herr Seibert’s photograph, purporting to be “ F. Saa- 
* ‘M. M. J.’ vol. xiv. pp, 274-281. f Ibid. + Ibid. vol. xy. p. 122. 
§ [bid. vol. xv. p. 103, || Ibid. p. 127. | Ibid. p, 104. 
** Thid. p. 209. 
