POLYCHAETE WORMS, PART 1 129 



Genus Exogone Oersted, 1845b 



Paedophylax Claparede, 18G8. Type (herein designated): Paedophrjlax veruger 

 Claparfede, 1868. 



Type (monotypy) : Exogone naidina Oersted, 1845b. 



All 3 species are ver}'' tiny, slender, threadlike, tapered slightly 

 anteriorl}'- and more so posteriorly, flattened ventrally, arched 

 dorsally. Prostoniium suboval to subrectangular, much wider than 

 long; palps much longer than the prostoniium, fused dorsally into a 

 rounded triangular mass, with or without an anterior notch, sepa- 

 rated ventrally by a wide depression. Tentacular segment short, 

 more or less distinct, the anterior part of which may form a fold 

 covering the posterior part of the prostoniium; with a single pair of 

 tentacular cirri, smaller than the dorsal cirri; with a pair of ciliated 

 nuchal organs between the eyes and tentacular cirri. Dorsal and 

 ventral cirri shorter than the parapodial lobes. Anal cirri 2-3, rather 

 long, subulate (median one may be short, fusiform) . Everted pharynx 

 crowned with a circle of papillae and a single conical tooth. With 

 long swimming setae at maturit}^. 



Large eggs, embryos or young (up to 5 setigers and resembling the 

 adult) attached to ventral surface of female, 1 to 2 per segment on 

 middle segments; young attached by a sort of peduncle of the anal 

 segment to the parapodia of the female. They are sluggish, moving 

 about very little. 



Key to the New England Species of Exogone 



1. Antenna short, siibcqual (fig. 31a). Anterior parapodia with setae of 3 kinds: 



simple curved upper one (fig. 31rf), compound spinigers (fig. 31c), compound 



falcigers (fig. 316). With or without dorsal cirri on setiger 2. . . E. verugera 



Median antenna longer than the lateral antennae, reaching a little beyond the 



middle of the palps (fig. 35d) 2 



2. Anterior parapodia with setae of 3 kinds: simple curved upper one, com- 



pound spinigers, compound falcigers. With dorsal cirri on setiger 



2 E. dispar 



Anterior parapodia with all setae compound, with short appendages (fig. 31e). 

 Dorsal cirri lacking on setiger 2 E. hcbes 



Exogone verugera (Claparede, 1868) 



Figure 31,a-d 



Paedophylax brevicornis Webster and Benedict, 1887, p. 721, pi. 2, figs. 40-41, 



pi. 3, figs. 42-45. 

 Exogone verugera Fauvel, 1923, p. 307, figs. 1 17, m-r. — Annenkova, 1938, p. 155. — 



Berkeley and Berkeley, 1948, p. 78, fig. 116. — Wesenbcrg-Lund, 1950a, p. 16; 



1950b, p. 49.— Day, 1953, p. 418; 1960, p. 317.— Eliason, 1962, p. 246. 



Description. — ^Length up to 8 mm., width up to 0.3 mm., seg- 

 ments 35-50. Prostomimn with 4 eyes (sometimes 6, an additional 



