214 NEW YORK STATE MUSEUM 
primitive condition as natatory organs and their functional adaptation 
to walking organs. The coxae of the swimming legs are distinctly seen 
in the type specimen. They are relatively small, considerably less than’ 
one half the length of the carapace, long at their inner margin ‘and 
subrhomboidal in general outline, the anterior and posterior margins being 
rather oblique and long. The fourth, fifth and sixth segments are longer 
than in the later species of Eurypterus and distinctly tubular, while the 
seventh and eighth are not nearly of the -relative size and width in 
E.remuipes or E. fischeri. Both are about equal in length, not 
longer than the preceding ones. The seventh segment is as wide as long 
and the eighth subcircular. The terminal spine is more than half as long 
as the preceding segment, shghtly curved. The metastoma is small, measur- 
ing little more than one third the length of the carapace, oval in form; 
the anterior portion slightly narrower than the posterior one. 
The genital appendages have been clearly seen in only one specimen, a 
female [pl. 26, fig. 2]. They are here so long that they reach to the posterior 
margin of the third sternite. The paired basal plates are visible only 
in faint outline. They were apparently of the usual shape. The first 
median lobe distinctly spreads in posterior direction and its paired extremi- 
ties are produced into relatively long laterally curved alae that extend 
to the posterior margin of the second sternite. The second median lobe 
is but little shorter than the first and of less, though uniform, width. The 
terminal paired appendages are long (as long as the second median lobe) 
and slender, slightly curved outward. 
Ornamentation. The type specimen shows on the last postabdominal 
segments where patches of the surface are preserved, very small, evenly 
distributed, sharply angular or pointed scales. 
Measurements. The type specimen is 136 mm long. Its carapace 
measures 28 mm in length and 34.7 mm in width; the preabdomen is — 
32.3 mm long and 39.4 mm wide; the postabdomen 42.2 mm long, 
31 -mm wide at its beginning and 12.5 mm at its posterior end. The 
telson 1s 30.4 mm. The metastoma is 9.5 mm long, the swimming legs are 
