111 
Hlab.—Fresh water; New Brighton, Clifton, New Dorp, fre- 
quent. (Plate LXIX., fig. 3.) 
We follow Kiitzing and Smith in referring P. mactlenta, Ehr., 
to this species. Ehrenberg’s figures, however, differ from theirs 
in being more linear, with less tapering apices.—Ra//s. 
The form described by Rabenhorst, Siiss. Diat., p. 45, t. VI., 
fig. 6, as Pinnularia oblonga, is obviously different from the 
_present species.— O’ Meara. 
NAVICULA MESOTYLA, Ehr. 
Navicula mesotyla, Kiitz., Bacill., p. 99, t. V., fig. 3, t. XXVIII, fig. 84; Ralfs 
in Prit. Infus., p. 895; Schumann, Diat. der Hohen Tatra, p. 77, pl. IV., fig. 51. 
Valve with triundulating margins terminating in obtuse 
rounded apices; strie slightly connivent; longitudinal free 
median space broader at the nodules and between the outward 
bulging undulations. fe 
Hab.—Fresh water; New Dorp, rare. (Plate LXIX., fig. 4.) 
NAVICULA MESOLEPTA, Ehr. 
Navicuta mesolepta, Kiitz., Bacill., p. 101, t. XXVIIL., fig. 73, t. XXX., fig. 34; 
Ralfs in Prit. Infus., p. 894; Van Heurck, Syn. Diat. Belg., pl. VI, figs. 10, 11. 
Pinnularia mesolepta, Sm., Syn., Vol. i., p. 58, pl. XIX., fig. 182. 
Valve elongated linear; margins triundulating, forming 
_ three equal central inflations, and terminating in broad, rounded 
extremities ; coste reaching to the median line. 
Hab.—Fresh water, scarce. New Dorp. (Plate LXIX,, , 
fig. 5.) : 
NAVICULA RHOMBOIDEs, Ehr. 
Navicula rhomboides, Kiitz., Bacill., p. 94, t. XXVIIL., fig. 45, t. XXX., fig. 
- 44; Rabenh., Siissw. Diat., p. 38, t. V., fig. 13; Sm., Syn., Vol. i., p. 46, pl. XVI., 
fig. 129, and Vol. ii., p. 90; Ralfs in Prit. Infus., p. 903; Donkin, Brit. Diat., p. 42, 
pl. VL., fig. 11; Brun, Diat. Alpes and Jura, p. 64, pl. VII., fig. 3f; Van Heurck 
Syn. Diat. Belg., pl. XVII, fig. 1; O’Meara, Rep. on the Irish Diat., p. 374, pl. 
XXXL, fig. 49; Schumann, Diat. der Hohen Tatra, p. 68. 
Valve rhomboid-lanceolate ; extremities slightly rounded ; 
striz exceedingly fine and parallel; central nodule but little 
developed, and hardly visible between two longitudinally juxta- 
posited cones formed by two median lines convergent toward the 
end nodules. 
Hab.—F resh water, frequent. (Plate LXIX., fig. 6.) 
