56 
RoPER_, on the genus Licmophora. 
autlientic slides of Professor Smith's of bofh species^ I have 
been enabled to satisfy myself^ and I trust any one who will 
investigate the subject, of the peculiarities which are the true 
characteristics of each. 
As I have had no opportunity of examining any living 
specimens, I am unable to determine, with any degree 
of certainty, whether there ought to be two or only one 
species in the genus, though this is a point which is open to 
much doubt. Kiitzing divides it into five, but his L. falgens 
is the Synedra fulgens of Smith, and his L. divisa 1 believe 
identical with Rhipidophora Dalmatica, and L. flabellata and 
Meneghiniana are evidently the same species ; so that in fact 
he has really only two, L. flabellata and L. radians. 
Professor Smith states that he only gives, " in accordance 
with the authority of his predecessors, two species of the 
present genus ; but he is far from satisfied that they are truly 
distinct .^^"^ In all the gatherings I have examined, I can 
detect no structural peculiarity that is not common to both^ 
and certainly there is no difi^erence in the form which will 
allow the F.V. of one to be called rounded at the upper ex- 
tremity,'' while the other is said to be truncate;" nor are 
the valves of one " attenuate at the larger extremity'^ 
whilst the others are " rounded," as stated in the specific 
characters by Professor Smith, and illustrated by the figures 
233 and 234, in t. xxxii, vol. ii of the * Synopsis.' 
The only real difibrence that can be detected in dried or 
prepared specimens is, that certainly 
some gatherings consist of frustules 
broadly cuneate on the S.V., and widely 
club-shaped on the F.V. (fig. 1, a, b) ; 
and at the same time, as far as our 
present evidence goes, this is combined 
with comparatively short valves, a shorter 
and less dichotomously branched stipes^, 
and, perhaps, some difference in the 
arrangement of the endochrome, as shown 
in fig. 234, t. xxvi, vol. i of the ' Sy- 
nopsis.' 
This last peculiarity, however, may 
arise from the time of year in which the 
specimen was gathered^ as the ocelli or 
riG. 1. 
specific name. It is curious that, according to the ' Infusionsthierchen/ p. 
221, Ebrenberg liad, in 1828, and again in 1831, in the 'Abhandl. der Akad.' 
of Berlin, described a small form under the name of " Ecliin. splendida" but 
this also was unknown at the time to Dr. Greville, and I have only included 
it in the synonomy of his species with much doubt. 
* 'Syn. JB.Diat./ vol. i, p. 85. 
