KESUN. 385 



h. Prostomium with a pronounced knob or boss on each side, the snout long and 

 tapering, its terminal process distally enlarged like a probe. 



Antiobacirum, gen. nov.' 

 hh. Prostomium with no such lateral bosses, simply conical, not thus prolonged, but 

 sometimes bearing a stalked mucro. 

 i. Pharynx with a fascia of elongate papillae on each side of the mouth. 

 j. Setae smooth (branchiae lacking on first two and last two pairs of parapodia 



in type) Ladice Kinberg. 



jj. Setae limbate (branchiae on all parapodia-bearing somites). 



Terpsichore Kinberg. 

 ii. Pharynx not with such lateral fasciae of elongate papillae . . Ammotrypane Rathke. 

 ee. Body without a midventral longitudinal furrow or a ventral sole. 



/. First setae borne on first complete ring caudad of mouth; setae partly smooth and 



partly serrulate-ciliate Dindymenidea, nom. nov. 



//. First setae borne in front of mouth; setae all smooth Travisia Johnston. 



Synonymy of Genera. 



A considerable number of the genera in this family are very imperfectly 

 known. Revisional work based upon plentiful material is much needed. In 

 the tabulation I have taken up the known genera on such bases as the published 

 accounts afford, though conscious of the slenderness of the basis of separation 

 in several cases. It seems better to maintain genera established, rather than 

 prematurely to merge them, until such time as our knowledge concerning them 

 shall permit fuller judgment and furnish evidence for better classification. The 

 division into Polyopthalminae and Opheliinae is retained without expressing a 

 personal opinion as to its naturalness. 



The type of Ophelina Oersted (1843), 0. acuminata Oersted, is identical 

 with the type of Anamotrypane H. Rathke (1843), A. aulogaster H. Rathke. 

 Hence the name cannot be used for a different generic group as is done by Hansen 

 and also by Mcintosh for the genus Antiobactrum. 



Dindymene Kinberg, being preoccupied in the Crustacea (1847), is replaced 

 by Dindymenides. 



Kesun, gen. nov.^ 



Body short, pointed at both ends, fusiform or grub-like. Body rounded 

 cylindrically, without ventral groove. Somites of the middle region triannulate, 

 while the others may be only biannulate or entire. 



Prostomium small, wholly smooth and rounded, without processes. 



Parapodial tubercles small and smooth, or wholly absent. No cirri or 



' Genotype, Ophelina brasiliensis Hansen. di'TOLo^ in front, and paKTpov, a stall or rod. 

 2 Gofeiute, ke, no, none, and sung, sun, lung or gill (pasun). 



