of the Virginian Coast. 



231 



Fam. ISTEREn)^. 



NEREIS {L.) Guv. 



PL. V, PIGS. 56-64. PL. VI, FIGS. 65-69. 



ITereis 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, divergir^g 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 ; 1st 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 



