RA 
Vie eR > 
REW YORK 
THE BOTANICAL 
MONTHLY MICROSCOPICAL JOBRNAL. 
JANUARY 1, 1877. 
” 
I.—On “ Navicula crassinervis,” “ Frustulia Saxonica,” and 
Navicula rhomboides, as Test-objects. 
By Rev. W. H. Datiincer, V.P.R.M.S. 
(Read before the Royvau Microscopican Society, December 6, 1876.) 
Puates CLXV. anp CLXVI. 
Amonest competent authorities there appears to be no longer 
any dispute as to the true relations of the diatoms that have 
hitherto received the separate designations in the above title. 
Professor H. L. Smith of America, and Mr. Kitton of our own 
country, doubtless two of the most competent living authorities, 
are agreed that they are but three names for the same species ; for 
both “ N. crassinervis” and “ F'. Saxonica” have no real existence, 
being but forms of NV. rhomboides.* But the vicissitudes through 
which opinion and conviction have passed, in less than two years, 
as precursive of this valuable conclusion, are interesting. In May, 
1875, Mr. Hickie, without the slightest doubt, declared F. Saxonica 
and N. crassinervis to be distinct species; and his conviction was 
reached not hastily, but after a study of the literature of the 
subject, after a careful investigation of his own collection of 
F. Sazxonicas, which was “a pretty extensive one,” and after ex- 
amining it, as a form properly entitled to its name, in company 
with Dr. Rabenhorst, “ both the discoverer and namer of the diatom 
in question.” + Besides which, he gives evidence, then clearly 
satisfactory to his own mind, that these three diatoms must be 
different, from the fact that to properly resolve them, they must 
be each placed differently in relation to the source of light.t 
But the great end he had in view was, to correct what he held 
to be a misconception on the part of Dr. Woodward as to the exist- 
— ence of longitudinal strie on “F'. Saxonica”; which Dr. Woodward 
© considered to be illusory, and which Mr. Hickie declared to be 
Le real; and the reality of which he contended was not only assured 
r+ by the evidence he brought, but by their having been perfectly 
i photographed by Herr Seibert. 
c» Lo this, with his usual thoroughness, and the aid of his match- 
Lu] 
CG * ‘M.M. J? vol. xv. pp. 278-281. + Ibid. vol. xiv. p. 33. t Ibid. p. 35. 
VOL. XVII. B 
