278 U.S. NATIONAL MUSEUM BULLETIN 2 27 



Judging from the few species of orbiniids that have been studied 

 in regard to their reproduction, yolky eggs may be spawned free or 

 fertihzed eggs laid in irregular ribbon-shaped clusters, C3dindrical or 

 pear-shaped gelatinous masses attached to the sand where the adults 

 live. They may have a very short swimming stage or pelagic stages 

 may be lacking. In the larvae, large ciliated branchiae appear early, 

 first appearing on segments 7-12 (setigers 5-10; Thorson, 1946; 

 Okuda, 1946; Horn and Bookhout, 1950, Anderson, 1959). 



The orbiniids are intermediate between the errant and sedentary 

 types of polychaetes. 



Key to the New England Genera of Orbiniidae 



1. Prostomium suboval (fig. 74a) or truncate, loaf-shaped . . Naineris (p. 278) 

 Prostomium conical (fig. 7Q,a,c) 2 



2. Postsetal neuropodial lobes of thoracic segments fimbriated, with vertical 



rows of postsetal papillae or podal fringe (more than 3 papillae, fig. 



75,a-c) Orbinia (p. 280) 



Postsetal neuropodial lobes of thoracic segments not fimbriated, with 0-3 

 papillae (figs. 74e; 76e) Scoloplos (p. 286) 



Genus Naineris Blainville, 1328; emend. Pettibone, 1957 



Naidonereis Malmgren, 1867. 

 Nainereis Mesnil and CauUery, 1898. 



Type (monotypy) : Naineris guadricuspida (Fabricius, 1780). 

 Contains only one New England species. 



Naineris quadricuspida (Fabricius, 1780) 



Figure 7A,a-c 



Naidonereis quadricuspida Webster and Benedict, 1887, p. 738, pi. 6, figs. 90-92. — 

 Whiteaves, 1901, p. 79. 



Nainereis quadricuspida Fauvel, 1927, p. 23, fig. ?),a-g. — Procter, 1933, p. 140. — 

 Annenkova, 1938, p. 171. — Wesenberg-Lund, 1950a, p. 29; 1950b, p. 74; 

 1951, p. 59; 1953, p. 56.— Uschakov, 1955, p. 260, fig. 87.— Not Berkeley 

 and Berkeley, 1956c, p. 544 { = N. tmcinata Hartman, 1957, published 

 June 14, 1957; = iV. berkeleyorum Pettibone, 1957a, published July 29, 1957). 



Description. — Length up to 80 mm., width up to 3 mm., segments 

 up to 130. Body elongate, subhnear, slightly flattened anteriorly, 

 tapering gradually posteriorly. Segments uniannulate and biannu- 

 late in thoracic region, triannulate in most of abdominal region. 

 Prostomium (fig. 74a) subglobular, shghtly wider than long, with 

 a pair of minute black eyes near posterior border (visible when living) . 

 A single apodous and achaetous tentacular or buccal segment which 

 may appear entire or 2-, 3-, or 4-ringed (perhaps representing more 

 than 1 segment). 



Branchiae begin usually on setiger 5 (4-6), continuing along rest 



