NAVICULA CUSPIDATA. 39 
fig. 68; Rabenh. Siissw. Diat. p. 39, t. vi. fig. 68, and Europ. 
Diat. p. 196. 
Plate VI. fig. 4. 
V. elliptical-lanceolate, attenuated into 
Frustule small. 
produced, capitate extremities; striz coarse, costate, 
about 24 in 001", connivent, reaching to the median 
line. 
Hab. Fresh water: common. 
Navicula ambigua, Ehrenberg. 
Navicula ambigua, Ehren. Amer. 1848, p. 129, t. IL. ii. fig. 9, and 
Mikrogeo. t. xv. B. fig. 15; Kiitz. Bac. p. 95, t. xxviii. fig. 66, 
Spec. Alg. p. 75; Sm. Synop. vol. i. p. 51, pl. xvi. fig. 149; 
Ralfs, in Prit. Inf. p. 902; Rabenh. Siissw. Diat. p. 40, t. vi. 
fig. 59, and Europ. Diat. p. 192. 
Plate VI. fig. 5. 
V. broadly elliptical-lanceolate with produced, narrow, 
capitate extremities; strie fine, delicate, 36 in 001", 
transverse, reaching to the median line. 
Hab. Fresh water: frequent. 
Navicula cuspidata, Kiitzing. 
Navicula cuspidata, Kiitz. Bac. p. 94, t. iii. figs. 24 & 387; Sm. Synop. 
vol. i. p. 47, pl. xvi. fig. 181; Ralfs, in Prit. Inf. p. 9085, pl. xii. 
fig. 5; Rabenh. Siissw. Diat. p. 87, t. v. fig. 16, and Europ. 
Diat. p. 170. 
Plate VI. fig. 6. 
V. broadly lanceolate, tapering into slightly produced, sub- 
capitate apices ; striz fine, delicate, 36 in -001", trans- 
verse, reaching to the median line. 
Hab. Fresh water : common. 
