HESIONIDAE. 185 



in this family. A critical revision based upon a careful restudy of type-species 

 is much needed. 



Key to Genera. 



a. With no tentacular cirri. 



Proboscis armed, with two stylets Taphun Webster it Benedict. 



aa. Tentacular cirri present. 



b. Two pairs of tentacular cirri (i)arap(Klia uiiirainous; {jrobascis with pai)illae, but no teeth or jaws). 

 c. Setae all simple; posterior parai)odia with a stoul, hooked seta, or cro(!het, projectiiifi; above 



base of notocirrus Ancislro.sijlliH Mcintosh. 



cc. Setae composite; parapodia with no such notopodial crochets Orseis Ehlers. 



bb. With more than two pairs of tentacular cirri, 

 c. With six pairs of tentacular cirri. 

 d. Parapodia uniramous. 



e. Proboscis unarmed Irina Grube. 



ee. Proboscis with two jaws and a stylet SyUidea Quatrefages. 



dd. Parapodia biramous. 



e. Notopodium small or rudimentary. 



/. Proboscis smooth, without papillae Podarke Ehlers. 



ff. Proboscis with a crown of i)apillae distally. 



g. Notopodial setae none or simple Psarmnate Sars. 



gg. Notopodial setae one in each notopodium, this composite. . Micropthalmus MecznikofT. 

 ee. Notopodium well developed (proboscis without papillae). 



/. Palpi slender, subfiliform, of same form as tentacles Orthodromus Ehlers. 



//. Palpi thick, much stouter than the filiform tentacles Oxydromiis Grube. 



cc. With more than six pairs of tentacular cirri. 



d. With seven pairs of tentacular cirri; palpi triarticulate Peribaea Ehlers. 



dd. With eight pairs of tentacular cirri. 

 e. Parapodia uniramous. 

 /. Tentacles two or none; proboscis unarmed. 



g. Tentacles very widely separated, as far apart as the anterior eyes; blade of com- 

 posite setae with a distinct subdental process extending toward or beyond the apex 



of the proximal tooth Hesione Savigny. 



gg. Tentacles nearer together than the anterior eyes; blade of composite setae more 



strongly bifid, with no subdental process or shield Dalhousieila Mcintosh. 



//. Tentacles three. 



g. Proboscis with two maxillae Leocratides Ehlers. 



ee. Parapodia biramous; tentacles three. 



Proboscis armed with two maxillae Leocrates Kinberg. 



Synonymy of Genera. 



Oxydromus Grube (1853) has as its type 0. fasciatus Grube; Stephania 

 Claparede (1870), Nereis flexuosa Delle Chiaji; and Ophiodromus Sars (1861), 

 0. vittatus Sars. These three species are found to be identical, flexuosa having the 

 priority. Hence Stephania and Ophiodromus are synonymous with Oxydromus. 

 Gyptis Marion and Bobretzky seems also clearly a synonym of Oxydromus. 



Psamathe Johnston (1836), type Ps. fusca Johnston, is identical with Cas- 

 talia Savigny (1820) aside from being preoccupied by Psamathe Raf. (Crustacea, 

 1814). The name was later written Psammate by Sars. It also seems necessary 

 to ehminate Kefersteinia Quatrefages (1865) since the species upon which based, 



