184 U-S. NATIONAL MUSEUM BULLETIN 227 



Family Paralacydoniidae, new family 



Type genus: Paralacydonia Fauvel, 1913. 



Paralacydonia Fauvel has been placed, along with Lacydonia 

 Marion and Bobretzky, in the subfamily Lacydoniinae under the 

 Phyllodocidae by Saint-Joseph (1888) and Fauvel (1914, 1923). 

 Lacydonia seems to show a closer relationship to the Phyllodocidae 

 and Alciopidae, while Paralacydonia seems more closely related to the 

 Nephtyidae. While increasing the number of polychaete families is 

 not particularly desirable, it has certain advantages over too much 

 lumping. Not much is to be gained by annexing a genus to a larger 

 family where it has few characters in common, since the major differ- 

 ences of the aberrant genus are apt to be obscured in the larger, better 

 known family. 



The following species have been described under Paralacydonia: 

 the type species, P. paradoxa Fauvel (1913, 1914) from the Mediter- 

 ranean; P. weberi Horst (1923) from the Netherlands Indies; P. 

 mortenseni Augener (1924) from New Zealand and referred later to 

 P. weberi by Augener (1927). The 2 species are dredged forms and 

 are similar in most respects. Uschakov (1958b) considers them to be 

 a single species. 



Body elongate, vermiform, subrectangular in cross section, having 

 the general aspect of a nephtyid. Prostomium subconical, w4th 4 

 very small anterior antennae. Tentacular or buccal segment achae- 

 tous and without appendages. Fu-st setigerous segment unu-amous, 

 rest biramous, supported by acicula. Parapodia with rami well 

 separated, with long cilia along interramal border (as in Nephtyidae) ; 

 each ramus with somewhat flattened presetal and postsetal lobes 

 (correspond to lamellae of Nephtyidae). Dorsal cirri small, conical; 

 ventral cu-ri digitiform (cirri not leaflike as in Phyllodocidae or 

 Lacydoniidae) . Notosetae simple. Neurosetae all compound (P. 

 weberi) or mostly compound with few lower simple setae (P. paradoxa; 

 thus setae not all simple as in Nephtyidae). Proboscis muscular, 

 cylindrical, unarmed. 



Contains only one genus. 



Genus Paralacydonia Fauvel, 1913 



Type (monotypy): Paralacydonia paradoxa Fauvel, 1913. Con- 

 tains only one New England species. 



Paralacydonia paradoxa Fauvel, 1913 



Figure 46 



Paralacydonia paradoxa Fauvel, 1913, p. 54, fig. 10; 1914, p. 118, pi. 7, figs. 1-9; 

 1923, p. 198, fig. 74,a-z; 1936b, p. 24.— Uschakov, 1958b, p. 416, fig. 1.— 

 Uschakov and Vv^u, 1959, p. 8. — Hartman, 1960b, p. 86, pi. 6. 



