THE EURYPTERIDA OF NEW YORK . 355 
Length of last postabdominal segment, 16.5 mm 
Width, 21.5 mm 
Length of telson, 33 mm 
Width, 23 mm 
Total length of original specimen (not distended as in fossil state), 
184 mm 
Largest carapace observed: 
Length of carapace, 28.5 mm 
Width of carapace, 40.5 mm 
Length of tergite, 23 mm 
Width, 73 mm 
A very large tergite [text figure 71] collected at Litchfield and possibly 
belonging to this species, has a length of ro cm and a width of about 37 cm. 
The largest telson observed measures: 
Length, 60.5 mm 
Width, 49 mm 
This telson, which undoubtedly belongs to P. macrophthalmus, 
indicates that the species attained at least twice the size of the complete 
individual represented on plate 69, figure 2 or a length of a foot and a 
half. If the large tergite from Litchfield belonged to this species, the animal 
reached a size of about 1.65 m or 5 feet, 5 inches. 
Remarks. The species P. macrophthalmus was founded 
upon the carapace of a young individual from the waterlime at Litch- 
field, Herkimer co., N. Y. At the same time a specimen lacking the 
carapace, and showing only four segments of the abdomen and the 
ventral side of the cephalothorax was made the type of another species, 
P.osborni. This specimen camie from the same horizon, and a locality 
a few miles distant from Litchfield, viz, Waterville, Oneida co. A sepa- 
rate metastoma [op. cit. pl. 80A, p. 16] of the same shape as that shown in 
the type of P. osborni was also referred to the latter species. 
While it was the correct procedure to erect different species for the 
carapace and the abdomen as long as the parts had not been found con- 
