44 NAVICULE. 
Navicula Crucicula, Smith. 
Stauroneis Crucicula, Sm. Synop. vol. i. p. 60, pl. xix. fig. 192; Ralfs, 
in Prit. Inf. p. 912, pl. vii. fig. 64; Rabenh. Europ. Diat. 
p. 261. : 
Plate VI. fig. 14. 
V. broadly lanceolate, or elliptical-lanceolate, slightly con- 
stricted beneath the obtuse apices; striz fine, close, 
slightly oblique, coarse and distant opposite the 
central nodule. : 
The appearance of a stawros, which this species presents, 
in the middle of the valve, when viewed with a low power, 
is deceptive; a careful examination with a high power 
shows the appearance to be produced by a peculiar modi- 
fication of the strie opposite the central nodule, where 
they are stout, opaque, and distant. 
Hab. Brackish water. Belfast Bay, Aug. 1849 (Prof. 
Smith). Estuary of River Blyth, Northumberland 
(A. 8. D.). 
Subsection VII. Valve cruciform ; stric fine, transverse, reaching 
to the median line, 
Navicula Follis, Ehrenberg. 
Navicula Follis, Ehren, Inf. 1888, p. 179; Mikrogeo. t. XVI. i. fig. 14, 
and ii. fig. 12, t. XVII. i. fig. 15, and ii. fig. 21. 
Navicula Crux, Ehren. Inf. p, 184. 
Navicula inflata, Kiitz. Bac. p. 99, t. iii. fig. 36. 1 and 2; Rabenh. 
Siissw. Diat. p. 41, t. v. fig. 10, and Europ. Diat. p. 191; 
Ralfs, in Prit. Inf. p. 899. 
Frustulia inflata, Kiitz, Syn. 1833, t. i. fig. 14. 
Plate V1. fig. 15. 
Frustule small. V. cruciform, with incurved sides and 
