42 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.10 



Family Onuphidae 



The Onuphidae have characteristic prostomial parts : there are 5 con- 

 spicuous occipital tentacles, including paired outer and inner lateral, and 

 a median unpaired one, each mounted on a more or less annulated base 

 called a ceratophore. In addition, there is a pair of simple, frontal an- 

 tennae at the anterior margin of the prostomium, and a pair of thick 

 palpi on the ventral side. Two anterior segments are apodous, the second 

 with (Onuphis and Rhamphobrachium) or without (Hyalinoecia and 

 Epidiopatra) tentacular cirri ; and succeeding rings are provided with 

 uniramous parapodia, although the dorsal cirrus carries a reduced noto- 

 acicular fascicle, indicating that it represents a greatly reduced noto- 

 podium. The first few (3 or 2) pairs of parapodia are sometimes greatly 

 enlarged and directed anteroventrally (Rhamphobrachium) , or they are 

 no longer than succeeding parapodia. 



The dorsal cirrus is simple, cirriform, sometimes giving rise from its 

 dorsal edge near the base to a branchial stioicture, which in turn may be 

 simple cirriform (Nothria), pectinately branched (Onuphis, Rhampho- 

 brachium), or more or less strongly spiraled (Diopatra, Epidiopatra). 

 Ventral cirri of the first few parapodia (2 to 10 or rarely more) are 

 usually cirriform, more posteriorly they are reduced to a flattened, cush- 

 ionlike, glandular pad. The postsetal lobe is frequently more or less pro- 

 longed, triangular, especially in anterior parapodia, but typically de- 

 creases in size farther back; the presetal lobe is usually inconspicuous 

 (though moderately large in some species, or m anterior segments of 

 some species of Nothria). 



Setae may include (1) simple, bilimbate, which may be present 

 throughout or absent from a few anterior segments, those in a superior 

 position usually provided with a longer, slenderer, bladed portion than 

 those more inferior; (2) simple or composite hooded hooks, with or with- 

 out lateral dentations in anterior segments; (3) pectinate (or comb) 

 setae in all or some segments; and (4) simple, j^ellow, hooded, bidentate 

 hooks, subacicular in position, in median and posterior segments. The 

 neuropodium is supported by 2 to 5 embedded, pale or yellow acicula, 

 often prolonged and projecting from the parapodial lobe. In some species 

 (Onuphis, Nothria, Rhamphobrachium) the inferior, bilimbate, simple 

 setae may be partly replaced by similar, composite setae designated com- 

 posite spinigers. 



The proboscidial armature is much like that in the family Eunicidae, 

 with which the Onuphidae may have their nearest affinities, but propor- 

 tionately much more delicate. Mandibles consist of a pair of thin, elon- 



