This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1900 Excerpt: ...(Navicula cuspidata).--Valve spear-shaped, with somewhat acute extremities. The striae parallel and distinct. There is a great similarity in the outline of these four species, especially to the unpractised eye. Of frequent occurrence in ditches. 243. Swollen Navicula (Navicula gibberuld).--The valves in this species ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1900 Excerpt: ...(Navicula cuspidata).--Valve spear-shaped, with somewhat acute extremities. The striae parallel and distinct. There is a great similarity in the outline of these four species, especially to the unpractised eye. Of frequent occurrence in ditches. 243. Swollen Navicula (Navicula gibberuld).--The valves in this species have rounded ends, and the sides have a convex inflation at the centre. Common in ditches. 244. Bordered Navicula (Navicula firma).--Valve narrow, gradually tapering to the rounded ends; a longitudinal line near each margin. Central nodule conspicuous. Striae fine. Common in ditches. 245. Constricted Navicula (Navicula amphisbcena).--Valve elliptical, with constrictions near the extremities, and rounded ends. Common in fresh and brackish water. (PL IV., fig. 32.) 246. Great Pinnularia (Pinnulana major).--From Navicula, this genus differs chiefly in the valves being ribbed instead of striated. This is a large and fine species, with the sides parallel and straight, except a slight marginal inflation at the centre, and blunt rounded ends. The central nodule large. Marshes and sluggish streams. 247. Narrow Pinnularia (Pinnularia viridis).--Valve narrowly elliptical, with the ends scarcely so rounded as the last, and without a central inflation. Ribs closer than in preceding species. Common everywhere. (PI. IV., fig. 9.) 248. Oblong Pinnularia (Pinnularia oblonga).--Valve spear-shaped (lanceolate) with rounded ends; the ribs distant from each other, and reaching to the line down the middle of the valve. Not so common as the above, but frequently mixed with it 249. Radiate Pinnularia (Pinnularia radiosd).--Smaller than the last, of similar form, but more pointed extremities, and the radiate ribs closer together. Common in fresh water. 250. Variable Pi...
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