New Diatoms from Honduras. Described by A. Grunow. 175 
productis acutiusculis, fascia marginali loculorum oblongorum an- 
gusta, loculis terminalibus ceteris paullum majoribus, striis punctatis 
subradiantibus, 14 in 01 mm. granulis oblongis (illis Stauroneis 
asperse similibus). Longit. •042- '058, latit. valvae ’02 mm. Tab. 
CXCV., Fig. 2. Eare in the Honduras gathering, Campeacby Bay. 
This is not a variety of M. Jelineckii, as 1 at first thought. The 
valves of that species have six very shallow depressions, three on 
each side of the median line, but which I cannot detect on M. rostel- 
lata. The dots composing the striae are shorter in Al. Jelineckii 
and form irregular longitudinal lines, those on Al. rostellata are 
arranged in an irregular quincunx like the dots on most of the 
varieties of Stauroneis aspera. 
AT. angulata Lewis, var. pusilla. M. minor valvis ovato lanceo- 
latus polis paululum productis, obtusiusculis, loculis 4-5 in ■ 01 
mm., striis ohliquis decussatis: 14-86 in - 01 mm., transversis 
tenuiorihus. Longit. '026 mm., latit. valvae '014 mm. Tab. 
CXCV., Fig. 3. Bare in the Honduras gathering. 
AT. ? reticulata Grun. ( Navicula reticulata Grun. in Hedwigia, 
l. c.). M. valvis bilobatis, lobis ovatis obtusis, isthmo profundo, 
margine cellulis majoribus (loculis ? ) cincto, structura duplex e 
cellulis irregulariter hexagonis, reticularis in area oblonga vel subor- 
biculari nodulum centralem ambiente deficientibus, et striis trans- 
versis subtilibus punctatis totam valvam obtegentibus (21-22 in 
• 01 mm.) composita. Longit. • 1— • 13 mm., latit. lobum • 034- * 37 
mm., latit. isthme • 014 mm. Color valvae exsiccata fuscescens. Tab. 
CXCV., Fig. 4. Bare in the Honduras gathering. 
Al. ? reticulata is allied to a series of diatoms considered till 
now to be species of the genus Navicula, but differing from all 
other Navicula} by a row of larger cells bordering the margin, and 
which seem to be analogous to the loculi of the Mastogloia. 
The following species I refer to this genu3 : Navicula mar- 
ginata Lewis, N. strangulata Grev., N. spectatissima Grev., and 
perhaps N. Janiaicensis Grev.; to these I can add four or five more, 
it would perhaps be better to found a new genus for these species, 
but before doing so a more critical examination into the nature of 
the marginal cells which seem to belong to the valve, and not to a 
second plate inserted between the valve aud connecting membrane, 
as in Mastogloia, is requisite. The central constriction is of no 
generic value. I have seen forms with a very slight constriction, 
and others with a lanceolate outline, and no constriction, without 
being able to separate them into distinct species, outline as well as 
granulation being exceedingly variable in this group of diatoms. 
I intend to describe a larger number of these forms in a future 
paper on Mastogloia. 
AT. marginulata Grun. Novara Exp. tab. 1, Jig. 12 (a trans- 
