NEREIDAE. 195 



h. Parasnatha present on all eisht areas Neanlhea Kinbcrg. 



hh. Paragnatha absent from one or more of the areas. 



/. Groups I, II, and V lacking Cirronerds Kinberg. 



ii. Group V, or V and VI, lacking Nereis Linn<>. 



gg. Paragnatha present on only one ring of the proboscis. 



/(. Present only on the maxillary ring Ccralonereis Kinberg. 



hh. Present only on the basal ring Eunerein Malmgrcn. 



//. Paragnatha not all conical and at the same time well separated. 



g. Paragnatha all of one form, very small, and arranged in dense series or pectinae. 

 (Groups I, II, V, and sometimes VI, VII, and VIII lacking.) 

 h. Stout crochets present in all but (he most anterior iiotopodia in addition to the 



ordinary setae Undnereis, gen. nov. 



hh. No crochets present. 



i. Group I lacking Puenoe Kinberg. 



ii. Groups I, II, V, and sometimes VI, VII, and Vllllacking. .Plalyncreis Kinberg. 

 gg. Paragnatha of two or three forms, conical and transverse, or else these and in addition 

 the pectinate type. 

 h. Of two forms, conical and transverse, separated. 



i. All grout)s present Pcrinerdfi Kinberg. 



ii. Groui) V lacking Areta Kinberg. 



hh. Of three forms, conical, transverse, and pectinate Psevdonerds Kinberg. 



Synonymy of Genera. 



Numerous other generic names have been proposed ; but nearly all of them 

 must be included in those designated in the analysis above. Until their type- 

 species shall have been restudied it must remain impossible satisfactorily to 

 place Typhlonereis and Phyllonereis of Hansen and Nossis of Kinberg. Not a 

 few species have been so inadequately described that it is now difficult or impos- 

 sible to identify them generically. Unless some other characters than those 

 presented by the proboscis and its armature shall be found it may become neces- 

 sary still further to combine some of the genera recognized here, since variations 

 in the arrangement and even in the form of the paragnatha are considerable in 

 some species, particularly between smaller specimens and the fully grown ones (C/- 

 Ehlers, Festsch. K. gesellsch. Gottingen, 1901, p. 112) discussion under Nereis 

 variegata Grube which he identifies with Mastigonereis podocirra Schmarda, 

 M. longicirra Schmarda, Paranereis elegans Kinberg, Nereis obscura Hansen, 

 A^. coerulea Hansen, iV. micropthalma Hansen, N. stimpsonis Grube, A^. fei'ox 

 Hansen and Naumachius pannosus (Grube) Kinberg. 



Since Ehlers, from a study of type-specimens and more abundant new 

 material, finds pannosus of Grube, as identified by Kinberg and by him made 

 the type of Naumachius, to be identical with elegans Kinberg, the type of Para- 

 nereis, these two genera must be merged; and since they in turn cannot be kept 

 distinct from Pseudonereis, all three must apparently be combined. Of these 

 Pseudonereis has the priority. Naumachius appears to have been based on the 

 epitokous form. 



