THE EURYPTERIDA OF NEW YORK 79 
shoveling edge, the dorsal or subapical position of the lateral eyes, as in 
Limulus, which would allow them to project above the mud, the peculiarly 
long, mobile and yet strong articulation of the carapace and first body 
segment, and the spiniform telson. 
It has been particularly pointed out by Holm [op. cit. p.g] that in 
EKurypterus fischeri the articulation between the carapace and 
the preabdomen must have been one of great mobility, as indicated by 
the broad slit, closed only by a membrane between the lateral fulcra. 
This connection was nevertheless so strong that the first preabdominal 
segment is most frequently found attached to the carapace in dismem- 
bered specimens. These facts suggest that Eurypterus may have been 
able to use the articulation between the carapace and the abdomen some- 
what like Limulus in pushing itself through the mud, a process which 
would be aided by the tail spine. 
On the other hand, there is good evidence that the species of Euryp- 
terus were able swimmers. We have elsewhere cited Holm’s description 
of the adaptation of the swimming legs in E. fischeri, evident 
in the sharp anterior keel of the organ and the arrangement of the articula- 
tion allowing the turning of the oar blade into a vertical position. Still 
more conclusive is the preceding pair of spineless slender legs, which 
would seem to have no other function than to serve as balancers and aid 
in swimming. | 
The combined evidence of the characters of Eurypterus is that it was 
a still little specialized, primitive genus, not yet wholly adapted to either 
crawling, digging or swimming, but could perform all these functions and 
was on the whole a sluggish animal. As it is not provided with strong 
organs of offense, it probably lived on worms or carrion. 
_ There are certain species of this genus, such as E. maria, which 
are distinguished by a remarkably slender form. As a rule these also have 
the eyes far forward on the small carapace. Their form indicates that 
they were more inclined to a swimming habit. Others have the broad 
head of a catfish and seem well adapted to resting on the mud and there 
