NAVICULA ELEGANS. 23 
stricted near the broad rounded: extremities; stris 
slightly connivent, fine, and very delicate, 54 in ‘001", 
reaching to the median line. 
Hab. Fresh water. Braemar (Dr. Greville) ; Elgin, Loch 
Leven, and other localities in Scotland (Prof. Gregory) ; 
River Coquet Northumberland, April 1869, abundant (4. 
S. D.). 
Navicula hebes, Ralfs. 
Navicula hebes, Ralfs, in Prit. Inf. p. 896; Rabenh. Europ. Diat. p. 189. 
Navieula obtusa, Sm. Synop. vol. i. p. 50, pl. xvi. fig. 140. 
Plate II. fig. 12. 
Frustule small. V.somewhat convex, elongate, elliptical, 
constricted beneath the dilated, broadly rounded ex- 
tremities ; striae sharp and distinct, about 35 in ‘001"; 
nearly transverse, not reaching to the median line, 
and shortest around the central nodule. Colour pale 
brown. 
Hab. Fresh water. Rassay Earth, Marl, Co. Down, 
Lough-Mourne deposit (Prof. Smith) ; Loch-Oich deposit, 
Caledonian Canal (A. 8. D.). 
Navicula elegans, Smith. 
Navicula elegans, Sm. Synop. vol. i. p. 49, pl. xvi. fig. 187; Ralfs, in 
Prit. Inf. p. 907; Rabenh. Europ. Diat. p. 182. 
Plate IV. fig. 1. 
V. elliptical, attenuated towards the slightly produced, sub- 
acute or slightly obtuse extremities ; striz radiate and 
curved, reaching to the median line, but much short- 
ened around the central nodule, distinct, costate, 24 
in :001". 
