. Fresh-water biology. Freshwater biology. MM. 45 (40) Valves obscurely reticulated and with some striae. Posterior and ventral margins straight, the latter extended into a point or spine. . , Scapholeheris Schoedler 1858 . 46 Body not compressed; shape more or less quadrate. Cervical sinus deep. Fornices and rostrum well developed. Head small, depressed. Valves almost rectangular, the infero- posteal angle of each produced into a longer or shorter spine; ventral margin with short, fine setae. Claws denticulate, not pectinate. One abdominal projection developed. Antennules small, about ali
. Fresh-water biology. Freshwater biology. MM. 45 (40) Valves obscurely reticulated and with some striae. Posterior and ventral margins straight, the latter extended into a point or spine. . , Scapholeheris Schoedler 1858 . 46 Body not compressed; shape more or less quadrate. Cervical sinus deep. Fornices and rostrum well developed. Head small, depressed. Valves almost rectangular, the infero- posteal angle of each produced into a longer or shorter spine; ventral margin with short, fine setae. Claws denticulate, not pectinate. One abdominal projection developed. Antennules small, about alike in both sexes, borne behind the rostrum. Summer eggs numerous; one ephippial egg. $ much like 9 ; hook on first foot. 46 (47) Color usually dark, often nearly black. Scapholeheris mucronata (O. F. MiiUer) 1785. Valves arched dorsally in old specimens; posterior and ven- tral margins straight; at their junction a spine often short, but often very long; in var. armala Herrick as long as ven- tral margin of valve. Anten- nules very small, almost im- movable, set behind beak. Post-abdomen short and broad, rounded at posterior end; 5-6 anal teeth. Length, 9, mm.; ^, ca. mm. The form with frontal spine has never been found in the United States. Common every- where in pools and lakes in weedy water, or swimming on its back near or at the MM. 1076. Scapholeheris mucronata. 47 (46) Color whitish or greenish;. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Ward, Henry Baldwin, 1865-1945; Whipple, George Chandler, 1866-1924. joint author. New York, John Wiley & sons, inc. ; [etc. ,etc. ]
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
