NO. 3566 EUPHILOMEDES MULTICHELATA—KORNICKER 7 
DESCRIPTION OF FEMALE.—Shell (figs. 4, 5a,b): oval in lateral view, 
highest near middle, widest behind middle; prominent rostrum, broad 
rostral incisure (figs. 4a-c). Rostrum anterior margin and _ shell 
anteroventral margin with scalloped outline formed by crescent-like 
marginal denticulations of flange (figs. 4f, 5b). Posterior one-third 
of dorsal margin with linear hinge depressed below outline of shell 
(fig. 47) ; posterior hinge element of each valve with angular sclerotized 
process; straight medial hinge element; anterior hinge element not 
prominent. Left valve broadly overlaps right valve along antero- 
dorsal margin (fig. 4b). Numerous muscle scars in front of middle 
of valve, located more anterior than on male (figs. 4a, e). Shell 
surface with irregular polygons distributed in shingle-like pattern, 
anterior to muscle scars (figs. 4e, 5a). 
Inner lamella broad, with vestibule; line of concrescence (identified 
as inner margin of clear zone of inner lamella) near middle of inner 
lamella anteriorly and ventrally, coming closer to outer margin 
posteriorly (figs. 4f-h). Selvage with wide, corrugated, lamella pro- 
longation with fringe of slender spines along margin. Faint striations 
along anteroventral inner lamella. About six long hairs, bearing 
secondary spines, in row on inner lamella behind rostrum (figs. 4f, 50). 
Small tapered hair on inner lamella below rostrum (figs. 4f, 56) fol- 
lowed by four hairs with secondary spines. Numerous tapered hairs on 
posteroventral part of inner lamella (fig. 4g). Numerous radial pore 
canals and false radial pore canals along anterior, ventral, and pos- 
terior margins (figs. 4f-h). Hairs with blunt and pointed ends 
(fig. 4d), scattered on rostral surface; tapered hairs of various lengths 
in row along ventral and posteroventral margins; additional hairs in 
normal pore canals, scattered over shell surface. Long tapered hair 
projecting backward from behind posterior hinge element of each 
valve (fig. 49). 
Dimensions: Length 1.07 mm, height 0.66 mm, width 0.51 mm. 
First antenna (fig. 5c): First and second joints with surface hairs. 
Second joint with distal bristles, one dorsal, one lateral bristle. Third 
joint with one ventral and one dorsal bristle, dorsal bristle with short 
hairs. Fourth joint with two dorsal bristles and one short and two 
long bristles near ventrodistal corner. End joints with eight bristles. 
Second antenna (figs. 5d—h): Exopodite with nine joints (fig. 5e); 
first joint elongate without bristle; second to ninth joints trapezoidal 
decreasing in width distally, without basal spines. Distal margin of 
second joint only with comb of long spines or stiff hairs (fig. 5h). 
Second and third joints each with bristles with denticulation along 
ventral margin, no natatory hairs (fig. 5g); fourth to eighth joints with 
long bristles with natatory hairs; ninth joint with four bristles (fig. 5f): 
long bristle with natatory hairs; shorter bristles bare, one about one- 
