GrevillEj on Neiv Diatoms. 
129 
•001"'. They are generally less close opposite the nodule, 
being 15 in one specimen, while in other parts of the same 
valve they are 20 in '001''. The fact is, however, that no 
dependence can be placed on characters of this description. 
Besides the examples already referred to, I have some from 
Long Island agreeing with the intermediate form of the 
species, and a slide containing a large series from a salt 
marsh at Cold Springs, Cape May, U.S., all the specimens 
being small and intermediate. In a drawing copied by my 
friend Mr. Roper from a specimen obtained by Professor 
Bailey from drift ice on the Hudson Eiver the leading 
characters are very prominent, especially the longitudinal 
ridge-like line ; and the median space is nearly as broad as 
in Professor Bailey^s figures. 
Navicula Zanziharica, n. sp., Grev. — Large ; valve ellip- 
tical, with the apices obtuse, somewhat produced ; strise 
minutely moniliform, divided by a blank line into two series, 
the one linear, very narrow, parallel with and next the 
median line, the other containing a sort of irregular spot 
opposite the nodule. Length -0074''. (Fig. 22.) 
Hab. Zanzibar; in slides kindly communicated by Professor 
H. L. Smith, of Kenyon College, Gambler, Ohio. 
A noble diatom, and, beyond dispute, an excellent species. 
The striae are obviously moniliform, slightly oblique, inter- 
rupted by a narrow blank line, not contracted opposite the 
nodule, gradually attenuated towards the ends, and disappear- 
ing before reaching the apex. On each side the median line, 
and parallel with it, is a narrow line or band of strise ; and 
these two bands, along with the median line itself, as they 
approach the ends become somewhat elevated and produced, 
and terminate in what may be regarded as a broad keel. 
Opposite the nodule, and midway between the margin and 
median line, is a curious spot composed of an irregular 
cluster of punctse, puckered, as it were, in the middle, while 
the surrounding strise are for a small space thrown into con- 
fusion. The first specimen which I found conveyed the 
impression that this singular appearance was the result of 
some accidental malformation ; but all the valves which have 
been subsequently discovered present the same character. 
The striae are 17 in '001'^ 
Navicula rimosa, n. sp., Grev. — Elliptic or elliptic-oblong, 
with a band of fine strise less than a third of the semi- diame- 
ter in width, a second very narrow band close to the median 
line, and a third narrow one between the two and not extend- 
ing to the ends ; the intermediate spaces obscurely punctate 
(cellulate). Length -0035" to -0060". (Fig. 25.) 
VOL. XIV. k 
