62 NAVICULEX. 
Navicula Liber, Smith. 
Navicula Liber, Sm. Synop. vol. i. p. 48, pl. xvi. fig. 183; Ralfs, in Prit. 
; Inf. p. 907; Rabenh. Europ. Diat. p. 180. 
Navicula maxima, Greg. Diat. of the Clyde, p. 15, pl. i. fig.18; Rabenh. 
Europ. Diat. p.172; Ralfs, in Prit. Inf. p. 909, pl. vii. fig. 75. 
Navicula linearis, Grun. in Wien. Verh. 1860, p. 546, t. i. fig. 2; Rabenh. 
Europ. Diat. p. 180. ; 
Plate IX. figs. 5a & 56. 
Frustule much elongated, on M. V. rectangular, slightly 
constricted in the middle, angles bevelled. V. linear, 
with rounded extremities; strice reaching to the median 
line, transverse, very fine, above 50 in -001"; dry 
valve straw-coloured. 
Distinguished from N. maxima by its smaller size, 
narrower valve, rounded extremities, curved median line, 
and finer strie, and by the much more prominent angles 
and less deeply constricted sides of the frustule on M.V. 
Hab. Marine: frequent. Coast of Sussex (Prof. Smith); 
Loch Fine (Prof. Gregory); coast of Northumberland, 
frequent in sand-gatherings (A. S. D.). 
C. V. linear-lanceolate ; strie oblique, distinct, and granular. 
Navicula aspera, Ehrenberg. 
Stauroptera aspera, Ehren. Amer. p. 184, t. I. i. fig. 12, iii. figs. 1 & 2, 
II. vi. fig. 20, III. vii. fig. 26, and IV. iv. fig. 1, Mikrogeo. 
t. xix. fig. 26; Rabenh, Siissw. Diat. p. 49, t. ix. fig. 1. 
Frustulia fulva, Bréb. in Herb. Binder. 
Stauroneis aspera, Kiitz. Bac. p. 106, t. xxix. fig. 12; Ralfs, in Prit. 
Inf. p.914; Rabenh. Europ. Diat. p. 250. 
Stauroptera Achnanthes, Ehren. Amer. p. 135, t. IIL. iii. fig. 7, and VI. 
iil. fig. 2, Mikrogeo. pl. XVIL, i. fig. 10; Rabenh. Siissw. Diat. 
p. 49, t. ix. fig. 2, 
Stauroneis Achnunthes, Kiitz. Bac. p. 106, t. xxix. figs. 20 & 22; Ralfs, 
in Prit. Inf. p. 913; Rabenh. Europ. Diat. p. 248. 
Stauronets pulchella, Sm. Synop. vol. i. p. 61, pl. xix. fig. 194; Ralfs, in 
