NAVICULA ANGLICA. 35 
capitate apices; strie reaching to the median line, 
transverse in the middle, slightly oblique near the 
extremities, fine, granular, about 40 in 001". 
Rabenhorst, in comparing this species with N. Amphis- 
bena, observes “ Nihilo minus ejus varietas esse mihi vide- 
tur.” He describes it as having convergent transverse and 
very delicate longitudinal strie; the latter, however, have 
no existence. It is a well-marked species, quite distinct 
from N. Amphisbena, and is by no means so common or 
generally distributed. I have never met with it in the 
North of England, where the latter species is common ; 
nor can I find any record of its occurrence in Scotland. 
By the kindness of Mr. T. Eulenstein I have been favoured 
with fine typical specimens from Stuttgart in Germany ; it 
forms one of his beautiful series of typical species, so highly 
deserving the attention of microscopists. 
Hab. Fresh water: not common. Lewes (Prof. Smith) ; 
near Hull, rare (Mr. Norman). 
Navicula anglica, Ralfs. 
Navicula anglica, Ralfs, in Prit. Inf. p. 900; Rabenh, Europ. Diat. 
p. 193. 
Navicula tumida, Sm. Synop. vol. i. p. 58, pl. xvii. fig. 146. 
Plate V. figs. lla & 118. 
Frustule small. V. elliptical, deeply constricted into pro- 
duced, short, capitate apices; strize connivent, con- 
‘spicuous, obscurely granular, 24 in -001", reaching to 
the median line. 
Hab. Fresh water. Bramley near Guildford, Nov. 1850 
(Mr. Capron) ; near Hull, rare (Mr. Norman) ; near Liver- 
pool (Mr. Comber). 
