170 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 10 



Family Arabellidae, new name 

 = Laidea Kfnberg 



The name Arabellidae is proposed to retain, distinct from the Lumbri- 

 neridae, a group of the superfamily Eunicea; the chief representative 

 genus is Arabella Grube. The body is more or less cylindrical, plain, 

 lumbrinerid in shape; the prostomium lacks appendages but may have 

 eyespots. Maxillae (rarely absent as in Biborin Chamberlin) are typi- 

 cally provided with a pair of long, slender carriers to which a median, 

 unpaired piece is attached on the ventral side. The maxillary pieces us- 

 ually include 5 paired pieces in 2 parallel rows (rarely reduced in num- 

 ber). The mandibles, situated on the lower side of the proboscis (rarely 

 absent as in Drilonereis nuda Moore), consist of a pair of flattened plates, 

 more or less fused along their median line. Parapodia are uniramous, the 

 notopodium represented only by an embedded notoacicular fascicle or also 

 a minute, papillar lobe, the neuropodium with only a fleshy lobe from 

 which the setae or also acicula project. Dorsal and ventral cirri are ab- 

 sent. Setae are of one kind only, simple limbate, somewhat geniculate, 

 with cutting edge smooth or dentate. Acicula are embedded {Arabella 

 Grube) or project from the parapodium {Drilonereis Claparede). 



The Arabellidae have their nearest affinities with the Lysaretidae, to 

 which they bear resemblances in the kind of proboscidial parts, setal and 

 other parapodial structures, but the Arabellidae lack the branchial struc- 

 tures and the small nuchal antennae common to the Lysaretidae; except 

 for these parts the similarities are striking. The Arabellidae differ from 

 the Lumbrineridae most conspicuously in these same parts, since the lat- 

 ter have their nearest affinities with the Eunicidae. 



The separation of this group was first recognized by Kinberg (1865, 

 p. 571), who erected the family Laidea. Kinberg defined it as follows: 

 "10 maxillae; no prostomial antennae; branchiae cirrose, mamilliform or 

 none." It should be noted, however, that Larymna Kinberg was included 

 in this family; but, since it has 3 prostomial antennae, it is actually a 

 Lysaretidae. The complete classification proposed by Kinberg follows: 



Maxillae I dentate, not uncinate [i.e., not falcate] 



Eyes 2, branchiae none Lais 



Eyes none, branchiae mamilliform .... Notocirrus 



Maxillae I dentate, uncinate [i.e., distally falcate] 



Maxillae I unequal Larymna 



Maxillae I equal Aracoda 



Although Arabella Grube had been erected many years earlier 

 (1851), it was entirely omitted from Kinberg's scheme; also, none of the 



