NAVICULA UNDOSA. 37 
broadly lanceolate, median, blank space. Colour yel- 
lowish brown. 
Hab. Fresh water: common. 
Navicula cryptocephala, Kiitzing. 
Navicula eryptocephala, Kiitz. Bac. p. 95, t. iii. figs. 20 & 26; Sm. 
Synop. vol. i. p. 58, pl. xvii. fig. 155; Rabenh. Siissw. Diat. 
p. 39, t. vi. fig. 71, and Europ. Diat. p. 198; Ralfs, in Prit. 
Inf. p. 901. 
Plate V. fig. 14. 
Frustule minute. V. elliptical-lanceolate, deeply con- 
stricted into produced, short, capitate apices; striz 
faint, 56 in 001", transverse, reaching to the median . 
line. 
Hab. Fresh water. Frequent in mountain-streams. R. 
Coquet Northumberland, May (A. S. D.). 
Navicula undosa, Ehrenberg. 
Navicula undosa, Ehren. Amer. p. 181, t. IL. ii. fig. 10, Mikrogeo. t. 
XXXIX. iii. fig. 90; Kiitz. Bac. p. 101, t. xxviii. fig. 83; 
Rabenh. Siissw. Diat. p. 41, t. vi. fig. 56, and Europ, Diat. 
p. 209; Ralfs, in Prit. Inf. p. 895. 
Navicula quinquenodis, Grunow, in Wien. Verh. 1860, p. 522, t. i. fig. 33. 
Plate VI. fig. 1. 
Frustule small. V. broad, short, elliptical; margins tri- 
undulate ; extremities produced, broad, subcapitate ; 
striz transverse, indistinct. 
Hab. Fresh water: not common. Near Hull (Mr. 
Norman) ; Whissonsett, Norfolk (Mr. Kitton). 
