54 | NEW YORK STATE MUSEUM 
tion which rests in the basal segments termed coxae. In correspondence 
with this activity these are narrow, elongate, subtriangular, armed with 
rows of teeth borne on the narrow end (guathobase or mandible) and form 
a manducatory edge. They increase in length with each successive pair 
and overlap like the tiles of a roof from the front backward seen in ventral 
view, and thus the coxae of the last pair of legs are not covered. Their 
sides are furnished with smooth gliding faces. In Eurypterus and Hugh- 
muilleria the fourth coxa possesses a circular perforation covered by a thin 
membrane and this is also present in Limulus. Holm first observed this, 
suggesting from its structure and position near the inner margin of the 
coxa which is exposed to the outside, that it was an auditory organ. 
This perforation is here figuredin Eurypterus remipes [pl. 7, 
fig.6,and Hughmilleria socialis [pl. 62, fig. 5]. 
Patten [1894] has indicated that the spines on the anterior portion 
of the gnathobase of Limulus serve as gustatory organs. The inference is 
proper that the thick, blunt, hollow spines observable in like position in 
Eurypterus fischeri [see Holm, op. ci. pl. 2, fig. 5-8] and other 
eurypterids [pl. 16, fig. 1] had a like function. 
The coxae of the second to fourth pairs of limbs of ‘Limulus bear 
a small, movable appendage behind the inner end of the manducatory 
edge, which is also found in 
the scorpion. This is known 
asthe epzcoxite. It is furnished 
with fine bristles and small 
brushes and has a tactile func- 
tion. Laurie discovered this 
articulated process in Slimonia 
[1893, p. 511] but was unable 
to determine how many and 
. — which pairs of legs bear it. 
Figurer2 Eurypterus fischeri Eichwald. Coxa of 
fourth left endognathite, seen from below (outside), Holm found epicoxites on the 
showing epicoxite at right and circular perforation, 
(From Eolm) | first to fourth pairs of the 
