150 U.S. NATIONAL MUSEUM BULLETIN 227 



The nereids are typically free living, mostly living in crevices and 

 burrows, where they construct galleries or a tube. Their general pat- 

 tern of activity centers around the tube (Clark, 1959). 



The terminology for the different types of setae in the nereids is as 

 follows: (a) Compound homogomph spiniger, distal tip of shaft even, 

 blade ends in slender fine tip (fig. 42e); (b) compound heterogomph 

 spiniger, distal tip of shaft uneven, blade ends in fine slender tip (fig. 

 42/); (c) compound homogomph falciger, distal tip of shaft even, 

 blade short, ending in blunt tip (fig. 42A) ; (d) compound heterogomph 

 falciger, distal tip of shaft uneven, blade ending in blunt, usually 

 hooked tip ; blades ma}^ be relatively long (fig. 44(/) or short (fig. 4:2g) ; 

 (e) compound homogomph cultrate or swimming seta, blade flattened, 

 paddlelike, characteristic of heteronereids or epitokes (fig. 44e); (f) 

 simple falciger, seta with blunt tip, formed by partial or complete 

 fusion of blade to shaft (fig. 44/i,). 



All four genera represented have the body vermiform, cylindrical, 

 with numerous segments; the first or tentacular segment achaetous and 

 apodous, with tentacular cirri 3 to 4 pairs. 



Key to the New England Genera of Nereidae 



1. Parapodia essentially uniramous, notopodium reduced to aii acicuium near 



the base of the dorsal cirrus; without ligules (fig. 41(i). Tentacular cirri 3 

 pairs (fig. 416). Proboscis smooth, without paragnaths or papillae. 



Lycastopsis (p. 150) 



Parapodia biramous (except for the first 2 pairs), with ligules (fig. i2,b-d). 



Tentacular cirri 4 pairs (fig. 45a). Proboscis with paragnaths or papillae . 2 



2. From the third setiger on, each parapodium with ventral cirri double (fig. 426) . 



Without notopodial ligules. Proboscis without paragnaths, with soft 



conical papillae on oral ring (fig. 42a) Ceratocephale (p. 152) 



Ventral cirri single. With notopodial ligules 3 



3. Proboscis with small pectiniform denticles or paragnaths (fig. 43, f,g). Pro- 



stomium suboval (fig. 43a). Sexual heteronereids with antennae and palps 

 turned ventrally, usually not visible dorsally (fig. 43/i). Platynereis (p. 154) 

 Proboscis with conical paragnaths (fig. 45,c-e). Prostomium subpyriform, 

 widest posteriorly, narrowed and rounded anteriorly (fig. 45a). Sexual 

 heteronereids, when present, with antennae and palps visible dorsally. 



Nereis (p. IGO) 

 Genus Lycastopsis Augener, 1922 



Type (monotypy): Lycastopsis bevmeri Augener, 1922 ;=L. pontica 

 (Bobretzky, 1872). Contains only one New England species. 



Lycastopsis pontica (Bobretzky, 1872) 



Figure 41 



Lycastis pontica Bobretzky, 1872, p. 1, pi. 14, figs. 1-4. 

 Lycastis littoralis Grube, 1872, p. 47. 



Lycastopsis beumeri Augener, 1922, p. 42. — Wesenberg-Luud, 1958, p. 14, figs. 

 9-10. 



