70 Transactions of the Royal Microscopical Society. 
Fig. 3, PI. LXXXI., is consequently incorrect. M. Petit’s Fig. 13 
fairly represents a transverse section of a frustule of Perrya. 
The genus Ceratoneis of Ehrenberg must be taken with some 
limitation, as it includes forms not belonging to the Nitzschieae. — 
F. Iv.] 
7th Tribe, Surirelle.® (Figs. 16, 17). 
The siliceous envelope of the Tryblionella very much resembles 
in constitution certain species of the genus Surirella. I, however, 
have never bad the good fortune to come across a transitional 
species, nevertheless one is able to comprehend the connection 
which exists between this tribe and the preceding ; but in the 
meanwhile one is able to understand the unity that exists between 
them. 
The endochrome in the third group invests only one side of the 
zone of the two valves ; if we imagine this layer to become divided 
above the zone, that is to say, in the middle, and which occurs 
from the longitudinal extension of the central opening, the result 
will be two layers of endochrome covering each valve. This dis- 
position of the endochrome is found in all the Surirelleae (Figs. 16 
and 17). To this disposition of the endochrome we have only to 
add the presence of alas on the margins of the valves to have the 
distinctive character of this tribe. 
[Dr. Pfitzer * says that this genus is very incorrectly called 
Surirella. The discoverer Turpin named it after a physician in 
Havre, Dr. Suriray ; it ought, therefore, to be called Suriraya. 
(“ Mit Unrecht schreibt man den Namen dieser Gattung uberall 
Surirella. Der Entdecker Turpin (a a 0, S 362) benannte sie 
nach einem Arzte Suriray in Havre und wir mussen daher wie 
von Bray Braya, von Berkeley Berheleya, so auch bier von Suriray 
Suriraya ableiten.”) I quite agree with Dr. Pfitzer that the 
name of this genus should be altered ; but unfortunately the old 
spelling has become so fixed, that there is, I fear, but slight chance 
of the correct form being adopted. — F. K.] 
8th Tribe, Svxedre/E. 
In the Synedreae the endochrome, with some slight modifications, 
present the same aspect as that in the Surirelleae and Eunotieae. 
The alae on the valves are absent, and this constitutes the differen- 
tiation of this tribe with the preceding. 
Genera, Staurosira, Synedra. 
9th Tribe, Eunotieje (Fig. 20). 
The arrangement of the endochrome is the same as that in the 
Surirelleae and Synedreae, but the layers cover the adjacent parts 
* Loc. cit., p. 107. 
