EEKANTIATE POLYCHAETA OF JAPAN. 179 



(îenus CeratocepJiale Malmgren. Auctor emend. 



Prostomiiim witli 2 tentacles and 2 palpi. First body-seg- 

 ment (peristomium) witliout parapodia, with 4 tentacular cirri on 

 each side. I'arapodium birarnous, with only inferior ligula, lacking 

 superior ligula. Dorsal cirrus filiform ; ventral cirrus bifurcated 

 or simple. Proboscis with soft papillae and 2 maxillae. 



Ceratoceiihale osaivai Izuka. 



19()o. Ceratocepliale osawai, Izuka. Journ. Coll. Sei. Imp. Univ., 

 Tokyo, Vol. XVII, Art. 11, pp. 1-37, Pis. I and IL 



Atocous phase : — Body very slender. Segments as many as 300. 

 Prostomium subhexagonal with broad base ; anteriorly concave 

 on the sides ; provided with two pairs of eyes, besides having a 

 pair each of tentacles and palpi. Peristomium with 4 pairs of 

 tentacular cirri. Proboscis protrusible, with soft papillae on the 

 anterior or maxillary ring, wliile the posterior or basal ring is 

 entirely destitute of tliera ; paragnathi absent. Arrangement of 

 the papillae : one in each of the areas I. and II. ; in IV. a single 

 papilla of quite insignificant lieight ; in 111. 17 — 27 in irregular 

 transverse rows. Maxilla) blackish In-own but translucent, with 

 7—9 teetli. 



Parapodia nearly similar tlii'oughout the body, all being bira- 

 7 nous ; only lower ligula of doisal ramus is present. Both dorsal 

 and ventral ciri'i arc simple. 



Pygidiinii willi a pair of slcndci- anal cii'ri. 



Bristles in part wilh falcate, and j]i part with setose, end-piece. 



JCpitocous phas3 : — This is tlio head-bearing anterior portion of 

 the original worm. The segments number 78 or less. They are 



