500 CLEVE, DIATOMS. 
at right angles, about 10 in 0,01 mm. In the centre of the 
valve is a large blank area, where the puncta are absent or 
as erased. Length 0,0o3—0,05 mm. Breadth 0,012—0,014 mm. 
— PI. 37, fig. 56. 
RB. quarnerensis Grun. (Verh. 1862, PI. IV, fig. 24)? It 
is with great hesitation I have determined the form Pl. 
37, fig. 53 as the above species. There is in the middle of 
the area a faint trace of a median line and of a very indi- 
stincet central nodule, from which characters the form may 
approach. the genus Glyphodesmus. The forme of the valve 
is sometimes a little cuneate (a). 
R.? marginulata Cl. & Grun. — Lanceolate with marginal 
strize, 15 in 0,01 mm., surrounding an apparently structure-less 
large area. Length 0,o042 mm. Breadth 0,009 mm. — Pl. 37, 
Tf 
Mr. Grunow found the same species in gatherings from 
the Seychells. According to Mr. Grunow the large area is 
pervaded by the shallow continuation of the marginal strize 
and has in the middle a median line, which I could not see 
with my lenses. 
Trachysphenia australis H. L. Smith. (Raphoneis australis 
H. IA Sm. - Am. Quarterl;! M: J: 1878, Pag lAJPLeII font; 
Tr. australis var.? Aucklandica Grun. in Van Heurck Syn. 
Pl. XXXVII, fig. 1). The genus Trachysphenia was establish- 
ed by Mr. Petit in 1877 (Diat. de Campbell pag. 32). The 
Tr. australis Petit 1. ce. Pl. V, fig 19, is large and has 6 puncta 
in 0,01 mm. It seems then to be different from Raphoneis 
australis H. L. Smith, which is 0,0128—0,0218 mm. in length and 
has 12 puncta in 0,01 mm. The specimens from Labuan are 
about 0,022 mm. in length and have 11 rows of puncta on 0,01 
mm. Similar forms have I seen in gatherings from Port Jackson. 
The cuneate form of the valve does not seem to be a constant 
characteristic, as I have found elliptic valves, to the sculpture 
agreeing with the cuneate ones. Such a specimen, var. elliptica 
Cl., has been figured on Pl. 37, fig. 54. 
Synedra commatata var. septentrionalis Grun. (Van Heurck 
Syn. P1. XL, fig. 5) Length 0,o5s4 mm. Strie 13 in 0,01 mm. 
S. affinis Kätz. — Strize 13 in 0,01 mm., area tolerably narrow. 
S. Hennedyana Greg. (Diat. of Clyde pag. 532, P1. XIV, 
fig. 108). 
S. erystallina var. Snmithii Grun. (Van Heurck Syn. Pl. 
XLII, fig. 10). 
S. fulgens Grev. (Sm. Syn. 1, pag. 74, P1. XII, fig. 103). 
