Page:The Eurypterida of New York Volume 1.pdf/377

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THE EURYPTERIDA OF NEW YORK
369

margin that corresponds to the doublure. The anterior region is covered with small linear or bean-shaped scales which in posterior direction become first crescentlike and then angular, increasing at the same time in size and decreasing in distinctness.

The coxae of the swimming legs bear small, widely distributed crescentic to circular scales that are directed outward. The other paired limbs show small crescentic scales on the basal segments and longitudinal lines of sharply angular scales on the distal segments.

The metastoma and the hastate part of the female opercular appendage are also provided with crescentlike scales.

On the sternites the scales become smaller, but very densely crowded, more prominent, and show an ever increasing tendency in posterior direction to become circular. The last tergite is covered on its anterior half with strongly raised, evenly distributed, black, round tubercles. Similar small circular scales are also observed near the anterior margin of the telson which otherwise is smooth.

Measurements. As we have at our disposal only two complete specimens, and these represent but immature individuals, the measurements of the mature specimens have been obtained by a series of proportions. We give first the measurements of specimen, plate 72, which is the best preserved of the complete individuals.

Millimeters
Length of carapace 39
Width 52
Length of largest tergite 25
Width 60+
Length of last postabdominal segment 26
Width 40?
Length of telson 39
Width 41
Total length of specimen 290
Length of chelicera on counterpart 115
Length of chela 26
Length of walking leg beyond margin of head 67
Length of swimming leg beyond margin of head 60