468 PROCEEDINGS OF THE NATIONAL MUSEUM vol.83 



the dorsal lobe assumes the shape of an acute triangle — N. procera 

 Ehlers, N. neonig7^pes, new species, N. Tiatans, new species, and 

 N. eakini, new species. Another series, in which there is a tendency 

 for the dorsal lobe to become quadrangular, includes N. zonata Malm- 

 gren, N. pseudoneanthes^ new species, N. mediator Chamberlin, 

 N . eucapitis, new species, and N. vexillosa Grube. Two species not 

 fitting into these series are N. limnicola Johnson, in which there is a 

 marked tendency toward reduction of all the lobes, and N. latescens 

 Chamberlin, in which both the dorsal lobes and postsetal lips are 

 l^roduced laterally. Nereis iiionterea Chamberlin i3 a Perlnereis. 



Genus NEREIS Linnaeus 



NEREIS (NEREIS) EUCAPITIS, new species 



FiGUBE 46 



Measurements. — Length, 15-30 mm ; width with parapodia, 4.5 mm 

 in anterior third of body; number of segments, 65-75. 



Description. — Prostomium broad (fig. 46, a), set off from palpi by 

 faint emargination, producing a flat appearance of dorsal surface of 

 "head"; provided with four black eyes set at lateral margins of 

 widened posterior portion of prostomium. 



Antennae (fig. 46, a) about as long as distance separating their 

 basoectal margins; diverging distally. 



Palpi elongated, cylindrical; basal portion of palpodes thickened 

 ventrally so that the two almost touch medially; distal halves of 

 almost uniform diameter (fig. 46, a) extending distally beyond tips 

 of antennae; palpostyles slightly narrower than palpodes, almost 

 spherical. 



Peristomium at least 2l^ times as long as segment 2 and somewhat 

 narrower (fig. 46, a), constricted in middle region; produced ven- 

 trally to form an almost smooth, flat lower lip ; peristomial cirri rel- 

 atively short, the longest reaching to palpostyle; cirrophores low, 

 smooth (fig. 46, a). 



Paragnaths light to dark brown; maxillary ring with smaller 

 teeth, basal ring with mostly larger teeth and a few smaller teeth; 

 I with a single small flat cone; II with a small oblique crescent of 

 about 10 rounded flat cones ; III with a patch of three irregular rows 

 of low cones ; IV with four transverse rows of many small points ; V 

 without teeth; VI Avith four large high cones; VII-VIII with a 

 continuous band of large tall cones, as in VI, and a patch of smaller 

 cones on the maxillary side of VII. 



Jaws strongly curved inward at middle; dark brown distally; 

 with six blunt rounded teeth and a plain distal portion as long as 

 two teeth. 



