168 Transactions of the Royal Microscopical Society. 
These Synedreae differ from S. crystallina by the very obscure 
longitudinal furrows near the margin of the valve, which are almost 
invisible. But as these furrows are very variable in some species, I 
dare not separate these forms into distinct species. 
Another variety of S. crystallina is perhaps 
S. ( crystallina var.) decipiens (Cleve and Grunow) from Cap. de 
la Neve. The valves of this form are only ' 2- - 21 mm. long, 
and '009 mm. broad, narrow, lanceolate, with rounded apices, 
very conspicuous median line and longitudinal furrows. Striae 111- 
in ’01 mm. 
Synedra Baculus Greg. var. minor Grun. S. valvis sublineari- 
bus, in media parte et ad polos vix incrassatis, linea media fere 
nulla, striis subtillime punctatis, validis (11-12 in '01 mm.) ante 
apices radiantibus. Sulc* longitudinales marginales inconspicuae. 
Longit. ‘22 mm., latit. valvae '0055- -007 mm. Tab. CXCIV., 
Fig. L 
Bare in the Honduras gathering. 
S. Baculus Greg, and S. superha Kg. have no true median line, 
but only a slight central depression running from one end of the 
valve to the other. S. superha has more or less conspicuous longi- 
tudinal furrows near the margin, and distinctly granulated striae 
(10^ in - 61 mm.). The valves are *02- ’024 mm. broad, but I 
have seen a small variety from Finmark with valves not more than 
•015 mm. in breadth. 
S. capillaris Grun. (n. sp.). S. angustissima valvis linearibus, 
in media parte vix incrassatis, linea media angusta distincta. Striis 
transversis subtilibus (19 in ’01 mm.). Longit. - 225 mm., latit. 
valv* -0015- '002 mm. PI. CXCIV., Fig. 2. 
Bare in the Honduras gathering. 
It is probable that many of the marine forms hitherto classed 
with the Synedras should be placed in the genus Toxarium of 
Bailey. I have not seen living specimens of T. undulatum, and am 
therefore unable to say whether the cell-contents are arranged in 
longitudinal plates or divided into numerous globules like those of 
S. fulgens and its allies. Pfitzer has seen the cell-contents of 
several marine Synedrae divided into numerous small portions, but 
he thinks they are not identical with the endochrome globules of 
his great family of Coccochromaticae. 
The valves of a Synedra like S. splendens are very different in 
many respects from those of S. fulgens, S. superha, &c., and it is 
possible that the cell-contents also differ in a manner which make 
a division of the genus necessary, like that of Staurosira Ehr. and 
Fragilaria. Staurosira (Dimeregramma Balfs ex parte Odontidium 
ex parte Fragilaria species plurime) is a genus nearly allied to the 
Synedreae of the type of S. splendens. Fragilaria virescens and 
its few allies are coccochromatic diatoms, as Plitzer has stated, and 
