of the Virginian Coast. 31 
Fam. NEREIDS. 
NEREIS {L.) Guv. 
PL. V, FIGS. 56-64. PL. VI, FIGS. 65-69. 
Nereis irritabilis n. sp. 
Body of nearly uniform size throughout the anterior 
three-fourths; posterior fourth tapering slightly. Number 
of segments over 200. 
Head (f. 56) convex, broadest between the anterior eyes, 
where the breadth nearly equals the length, decreasing 
slightly behind, rapidly in front. 
Eyes, circular, small, lateral ; front pair placed at pos- 
terior third ; posterior pair near the back of the head, half 
the diameter of the front pair. 
Antennae, arising close to each other, delicate ; length 
a little more than half the length of the head. 
Palpi, about as long as the head, diverging rapidly, ex- 
tending a little beyond the antennae ; basal portion stout ; 
terminal article slender, elongate. 
First segment, as long as the following segments, arching 
forward, so as to encroach slightly on the head. 
Tentacular cirri, 4th reaching to 5th segment; 2d one- 
third to one-half as long as 4th ; Ist and 3d, a little shorter 
than 2d, equal. 
Feet (figs. 58-62), on the anterior part of the body, com- 
pact. Superior lingula stout at base, conical, reaching a 
trifle beyond the upper ramus. The upper lip of the 
superior ramus is a mere papilla on the anterior basal por- 
tion of the lower lip. The lower lip has the same form as 
the upper lingula, but is a little shorter, and not quite so 
large at base. The lower ramus is a little shorter than 
the upper, is divided by a shallow incision into anterior 
and posterior lips, of which the anterior is slightly the 
longer, and is further divided at the end into two rounded 
