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 Taphus Webster & Benedict. 



aa. Tentacular cirri present. 



6. Two pairs of tentacular cirri (parapodia uniramous; proboscis with papillae, but no teeth or jaws). 

 c. Setae all simple; posterior parapodia with a stout, hooked seta, or crochet, jirojecting above 



base of notocirrus Ancislrosi/llis Mcintosh. 



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



66. With more than two pairs of tentacular cirri. 

 c. ^\'ith six pairs of tentacular cirri. 

 d. Parapodia uniramous. 



e. Proboscis unarmed Irma Grube. 



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



dd. Parapodia biranious. 



e. Notopodium small or rudimentary. 



/. Proboscis smooth, without papillae Podarke Ehlers. 



ff. Proboscis with a crown of papillae distally. 



g. Notopodial setae none or simple Psamtnate Sars. 



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

 ee. Notopodium well developed (proboscis without papillae). 



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



//. Palpi thick, much stouter than the filiform tentacles Oxydromus 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 ven,' 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 Sa\'igny. 



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



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



//. Tentacles three. 



g. Proboscis with two ma.xillae Leocratides Ehlers. 



ee. Parapodia biramous; tentacles three. 



Proboscis armed with two maxillae Leocrates Ivinberg. 



Synonymy of Genera. 



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

 Claparede (1870), Nereis flexuosa Delle Cliiaji; 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 eliminate Kefersteinia Quatrefages (1865) since the species upon which based, 



