LUMBRINEREIDAE. 325 



rendus Soc. biol., 1914, 77, p. 490) also lives parasitically in a terebellid, but the 

 regressive modifications are much less pronounced. Ophiuricola cynips, described 

 by Ludwig (Zool. anz., 1905, 29, p. 397) as parasitic and galligenous inswelUngs 

 on the arms of the deep-sea Ophiura tumulosa (Liitken and Mortensen) is too 

 briefly characterized to make it possible definitely to place it, though it may be a 

 lumbrinereid. 



Key to Genera. 



a. Dorsal cirrus rudimentary Lumbrinereinae. 



b. Parasitic forms; jaws more or less atrophied. 



c. Eyes none (parasitic in Terebellides) Haematocleptes Wii6n. 



d. Setae not emerging from parapodia; maxillae I strongly atropliied. 

 dd. Setae emerging freely from parapodia, two series of fascicles; maxillae I well developed. 



Labidognathus Caullery. 

 cc. Four eyes present. 



d. Lower jaws moderately developed (parasitic in Syllidae) Labroslratus St. Joseph. 



dd. Lower jaws more atrophied (jmrasitic in Bonellia) Oligognathus Spengel. 



bb. Not parasitic; jaws normally developed (excepting in Biborin). 



c. With only simple, mostly capillary and laminate setae, no hooked spines or crochets. 

 d. First two somites achaetous. 



e. With no maxillae Biborin Chamberlin. 



ee. Maxillae well developed. 



/. Blades of maxOlae I in form of stout hooks which may be mesally denticulate only at base. 

 g. Third and fourth maxillae reduced to hooks. 



h. Maxillae I with three slender supports Loranda lunberg. 



hh. Maxillae I with but two supports Drilonereis Claparede. 



gg. Third and fourth maxillae dentate plates, not reduced Arabella Grube. 



}}. Maxillae I not in the form of hooks or strongly uncate plates; normally dentate along 

 entire mesal edge. 



g. With four pairs of maxillae Pterothrix, gen. nov.' 



gg. With five pairs of maxillae. 



h. Small no tocirri present; setae few, dentate at base of limbus .. TVotoaVrjis Schmarda. 

 hh. No notocirri obvious; setae simply limbate, not dentate. .. .Notopsiius Ehlers. 



dd. First somite only achaetous; five pairs of jaws Aracoda Schmarda. 



cc. Crochets or compound setae or both present, more than one in most parapodia of posterior 

 region. 



d. With digitate branchiae on setigerous lobes of parapodia Ninoe Kjnberg. 



dd. No branchiae. 



e. Crochets single, sometimes aciculiform but always hooded. 

 /. First maxillae in form of strong hooks; III and IV not dentate. .Cenogemts, gen. nov. 

 ff. First maxillae not in form of hooks, strongly dentate, with long posterior supports. 



Guards of crochets strongly asymmetrical Cenothrix, gen. nov. 



ee. Crochets not single. 



/. With four pairs of maxillae. 



Maxillae I in form of stout hooks; crochets numerous in posterior region. 



Lumbrinereis Blainville. 



//. With five pairs of maxillae Larymna Ivinberg. 



aa. Dorsal cirri well developed, usually foliaceous Lysareiinae. 



b. Prostomium anteriorly with two laterally directed processes Enonella Stimpson. 



66. Prostomiiun with no such anterior processes. 



c. Carriers of maxillae I short, forming broad blades Lysarete Kinberg. 



cc. Carriers of maxillae I long and filiform. 



' Genotype, Nolocirrua scoticus Mcintosh. 



