THE EURYPTERIDA OF NEW YORK SI 
strikingly long last two pairs, different groups have developed differently 
in regard to the preceding legs. In some these have remained relatively 
short and shaped as in Dolichopterus, in others they have grown in cor- 
respondence with the last pairs, are highly spiniferous, the spines becoming 
very long and increasing greatly in number [pl. 49, fig. 6] and in others 
again the spines of the first three pairs show a tendency to become flat 
and broad. | 
In Woodward’s well known restoration of Stylonurus the animal is 
given three short pairs of anterior legs and two very long, subequal pairs 
of posterior legs, the latter being regarded as for swimming, and the 
former for walking. Laurie, who recognized the probable derivation of 
Stylonurus from Eurypterus through Drepanopterus, considered the sixth 
pair as being reduced ‘‘ from the typical digging foot to a purely crawling 
one,” adding: ‘‘ This may indicate more purely littoral habits, or a more 
active predatory existence, demanding rapid locomotion rather than firm 
anchorage.’’ Beecher’s life size restoration of S. excelsior accepted 
Woodward’s conception of the posterior legs, adding only the bladelike 
appendages of the short first three pairs of legs observed by Hall and 
Clarke in the first and second endognathites of S. excelsior and sug- 
‘ 
gested that these legs ‘‘served partly as swimming organs.” 
From the somewhat different restoration of Stylonurus, at which we 
have arrived in this paper and which is fully set forth in another place 
we infer that the animal was comparable to the existing gigantic 
Japanese spider crab, which some of its species rivaled in size. Like 
that grotesque creature it probably used its long hind legs to shove 
itself forward over the muddy bottom, while its short front legs indicate 
that the head lay near the bottom, the front legs being used for walking 
and grasping, and perhaps also, where the spines are broadened, as swim- 
ming organs. The extremely long styliform telson frequently with a blunt 
extremity, may have served less as a protecting than as a supporting 
organ of the long abdomen, and have aided in righting the awkward 
creature when it was overturned. 
