NAVICULA ROSTRATA. 15 
Navicula clavata, Gregory. 
Navicula clavata, Greg. Trans. Micr. Soc. vol. iv. p. 46, pl. v. fig. 17; 
Ralfs, in Prit. Inf. p. 898. 
Navieula Lyra, Rabenh. Europ. Diat. p. 178. 
Navicula Wrightit, O’Meara, Quart. Micr. Journ. vol. vii. n. s. p. 116, 
pl. v. fig. 4. 
Plate II. fig. 8. 
V. broadly elliptical, extremities produced, broad, and 
rounded ; striz granular; marginal band broad, and 
of equal width except near the extremities, where it 
is abruptly separated from the median band; unstriated 
area lunate, with everted narrow extremities reaching 
to the margin of the valve at the base of its apices. 
Hab. Marine. Lamlash Bay Isle of Arran, Glenshira 
sand (Prof. Gregory); coast of Northumberland (4. 8. D.). 
Navicula rostrata, Ehrenberg. 
Navicula rostrata, Ehren. Berlin, 1840, p. 18; Kiitz. Bac. p. 94, t. iii. 
fig. 55; Ralfs, in Prit. Inf. p. 901; Rabenh. Siissw. Diat. 
p. 37, pl. vi. fig. 52, and Europ. Diat. p. 197. 
Navicula tumens, Sm. Synop. vol. i. p. 52, pl. xvii. fig. 150; Ralfs, in 
Prit. Inf. p. 900; Rabenh. Europ. Diat.-p. 192. 
Navicula sculpta, Ehren. Mikrogeo. t. X. i. fig. 5; Ralfs, in Prit. Inf. 
. 900. 
Thies ae Rabenh. Europ. Diat. p. 227. 
Plate II. fig. 9. 
V. elliptical, gradually attenuated into produced obtuse 
extremities; strie slightly inclined, granular, about 
36 in 001"; marginal band broad, with an indefinite 
inner border, and much shortened in the middle, on 
one side of the valve; median band narrow, linear, and 
bordering the median line, which is narrow; unstri- 
ated area narrow sublunate, with indefinite margins. 
There can be no doubt whatever that the synonyms of 
