284 NEW YORK STATE MUSEUM 
It is proper to say here that the restorations of S. loganti 
and S$. excelsior have always looked unnatural to us in leg con- 
struction, because it is not apparent how the two very different sets of legs 
could have been used harmoniously. Woodward and Beecher were not 
in accord in their opinions as to the use of these legs; the former considered 
the long legs as the swimming feet [see his description of S. logani] 
and the short ones as the walking feet, while Beecher per contra considered — 
the long legs as the crawling feet [see 1900, p. 149]. As to the latter con- 
ception, it is unintelligible to us how the creature could have balanced 
itself on these four legs or could have taken up its food without corres- 
pondingly long prehensile organs, much like the chelae of Pterygotus and 
those of the recent sea spiders. The short anterior legs of the resto- 
ration would seem to have been hardly competent to propel the huge body 
in swimming and their position at the front of the carapace would have 
scarcely allowed their effective use for walking without the assistance 
of the other legs. 
The gradually lengthening series of legs suggests to us that they, 
all combined, were functional in crawling, the long hinder pairs, on account 
of their stronger curvature and backward direction, reaching the same 
level as the shorter forward pairs with their terminal claws, thereby carrying 
the body as it is carried in nearly all crustaceans and arachnoids, on four 
or more pairs of legs. | 
There is a difference of opinion as to whether the last pair or pairs were 
the more active in swimming, as in the other eurypterids, or the first three 
pairs, as suggested by Beecher. On one hand analogy with the other 
eurypterids would indicate the use of the last pair of legs as swimming 
organs, and it would constitute a wide departure if this group reversed 
the functions of the fore and hind limbs. On the other hand, these hind 
legs show none of those characters which naturally accompany a swim- 
ming function, such as a widening of the joints and an intricate artic- 
ulation insuring rigidity of the legs, while the preceding legs, 1n some species 
as S$. cestrotus, are provided with a dense fringe of contiguous 
