NO. 3 HARTMAN : ORBINIIDAE, APISTOBRANCHIDAE, PARAONIDAE 335 



and 90 to 105 segments. The setae in abdominal segments are long, 

 very slender and resemble those of epitokous stages. The prostomium is 

 a plain rounded lobe a little longer than wide, without antenna or eyes. 

 Branchiae are first present from the fourth setigerous segment and 

 number 10 pairs. (Southern reported 8, 11 to 14 pairs). The thoracic 

 notopodial lobe is long, digitiform, about a third to a half as long as its 

 accompanying branchia but slenderer. The notopodial lobe is continued 

 in abdominal segments but diminishes in size ; it can be distinguished be- 

 yond the middle of the body. Setae are entirely slender and capillary 

 except that posterior notopodia have lyre setae, numbering one or two 

 in a group and accompanied by long slender setae. The posterior end 

 terminates in a pygidium with 3 cirriform processes. 



The individuals from the San Pedro Basin, California, agree with 

 those described from Europe (Southern, 1914, Eliason, 1920) except 

 that they are smaller. Another from north of Coche Island, Venezuela, 

 in 13 fms, mud (A 32-39), has branchiae present from the fourth seti- 

 gerous segment and they number 11 pairs. This individual measures 

 about 12 mm long and nearly 2 mm across, but in other respects it re- 

 sembles the smaller ones from the Pacific Ocean. 



Distribution. — Ireland (Southern, 1914), western Europe (Eliason, 

 1920), France (Fauvel, 1927); San Pedro area, California, in 11 to 

 220 fathoms. (See chart of distribution). 



LONGOSOMIDAE Hartman, 1944 



This family is known for a single species. It may have its affinities 

 with members of the Paraonidae (see above) but the recent discovery of 

 large paired palpi, resembling those of spioniform annelids, allies it to 

 disomid and magelonid families as well. The prostomium is a small, de- 

 pressed, triangular lobe without appendages. A pair of long, large, longi- 

 tudinally grooved palpi is attached in transverse slits between the pros- 

 tomium and peristomium in dorsolateral positions. The body is divided 

 into an anterior region of nine short setigerous segments and an abdomen 

 with greatly prolonged cylindrical segments. The eversible proboscis is an 

 unarmed epithelial pouch. Long cirriform branchiae are limited to one 

 pair to each of the thoracic segments. Parapodia are biramous and have 

 weakly developed lobes. Setae are entirely simple and consist of at least 

 three kinds. All segments have limbate, distally pointed ones; the first 

 neuropodium has modified recurved hooks (Hartman, 1944, pi. 27, fig- 

 3a) ; and abdominal parapodia have subuluncinate setae (pi. 43, fig. 8) 

 in anterior series accompanying limbate setae. 



