NO. 3566 EUPHILOMEDES MULTICHELATA—KORNICKER 3 
in lateral view except by transmitted light. Posterior hinge ele- 
ment of each valve consisting of angular sclerotized process (figs. 
le, h); medial hinge element straight; anterior hinge element not 
prominent. Left valve broadly overlapping right valve along an- 
terodorsal margin (fig. 16). Fifteen or more individual muscle scars 
clustered near middle of valve (fig. 1a); large scar situated some 
distance above others. 
Inner lamella broad, terminating at each end of dorsal hinge. 
Line of concrescence about half-way between middle and outer margin 
of inner lamella. Selvage with wide, corrugated, lamellar pro- 
longation, having fringe of slender spines along outer margin; no 
parallel striations observed on inner lamella. Six or seven long hairs, 
some bearing secondary spines, forming row on inner lamella be- 
hind rostrum (figs. 1d, 7); inner lamella below rostrum with small 
hair followed by wide space and then about four hairs (fig. 1/); 
about 16 hairs on posteroventral part of inner lamella (figs. le, h). 
Marginal pore canal with minute tapered hair between first and 
second crescent-like denticulation on anteroventral margin of ros- 
trum; another pore canal with minute hair near 12th to 15th denticle 
(figs. 1d, 2). Additional marginal pore canals more or less evenly 
spaced along ventral and posteroventral margin. Hairs with either 
pointed or blunt ends distributed on rostral surface (fig. 1g), some 
forming row near margin of shell; long slender hairs with pointed 
ends forming row that is closer to edge posteriorly and is near ven- 
tral and posteroventral margins of valves; additional hairs coming 
from normal pore canals; a long tapered hair projects backward from 
base immediately behind posterior hinge element of each valve 
(figs. le, h). 
Dimensions: Holotype length 1.04 mm, height 0.60 mm, width 
0.57 mm. Length of specimens ranges between 0.96-1.04 mm 
(Kornicker, 1959, p. 231). 
First antenna (fig. 2a): First joint with about seven clusters of 
short hairs on lateral surface. Second joint with clusters of long 
hairs on medial surface; spines projecting from ventral margin and 
distally with a dorsal and lateral bristle; a distal ventral bristle 
observed only on one of five specimens examined; all bristles bare or 
with short hairs distally, none with wreaths of long hairs. Third 
joint with one ventral and two dorsal bristles, the longer dorsal 
bristle provided with wreath of long hairs near middle and short hairs 
distally; other dorsal bristle bare or with short hairs distally; ventral 
bristle with short hairs on most specimens. Fourth joint with two 
dorsal bristles, each with wreaths of long hairs, and one short and 
three long ventral bristles subdistally; bristles bare or with short 
hairs distally. Fifth joint inferred to be inserted ventrally between 
