NAVICULA HENNEDYII. il 
finite inner border; median band narrow, close to the 
median line, and with an indefinite outer border ; 
unstriated area broad, semilunate, and covered with 
irregularly scattered, conspicuous granules. 
Hab. Marine. Lamlash Bay Isle of Arran, Loch Fyne 
(Prof. Gregory). Discovered by Ehrenberg in the clay- 
marl of Agina, one of the oldest deposits in which the 
remains of diatomes have been found. 
Navicula nebulosa, Gregory. 
Navicula nebulosa, Greg. Diat. of the Clyde, p. 8, pl. i. fig. 8; Ralfs, in 
Prit. Inf. p. 898; Rabenh. Europ. Diat. p. 179. 
Plate IL. fig. 2. 
V. oval, with a slight tendency to angularity in the middle, 
and to acumination at the apices; strie fine, granu- 
lar, rather faint; marginal band narrow, and of even 
width throughout; median band narrow, linear, and 
contiguous to the median line; unstriated area semi- 
lunate. 
A much more finely striated species than N. Hennedyii. 
Hab. Marine. Lamlash Bay Isle of Arran (Prof. Gre- 
gory). 
Navicula Hennedyii, Smith. 
Navicula Hennedyii, 8m. Synop. vol. ii. p. 93; Greg. Trans. Micr. Soc. 
vol, iv. pl. v. fig.3; Ralfs, in Prit. Inf. p. 898, pl. vii. fig. 69 ; 
Rabenh. Europ. Diat. p. 178. 
Plate II. fig. 3. 
V. oval; striz granular, distinct, about 24 in -001"; mar- 
ginal band with a crescentic inner border and gradu- 
ally narrower towards the extremities, median band 
