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 cres- 
—centic 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 appen- 
dage 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 di- 
rection to become circular. The last tergite is covered on its anterior 
half with strongly raised, evenly distributed, black, round tubercles. Simi- 
lar small circular scales ate also observed near the anterior margin of 
the telson which otherwise is smooth. 
Measurements. As we have at our disposal only two complete speci- 
mens, 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.... 0.2... . eee eee eee ees 39 
Width o 2. ce ee eens - 52 
Length of largest tergite... 0.1... cece ee eee ees 25 
Width. 0. cee ce tee cee ee ee eee eens 6o + 
Length of last postabdominal segment.................... 26 
Width 2.0.0... ce cece eee ee ee eee nees 40? 
Length of telson... 0... eee ee eens 39 
Width .. eee eee e tence ne ees AI 
Total length of specimen..................000. Senet eens 290 
Length of chelicera on counterpart. ......... 0.2.0. .00008. ITS 
Lerigth of chela.... 0... ee eee 26 
Length of walking leg beyond margin of head... .......... 67 
Length of swimming leg beyond margin of head........... 60 
