NO. 3 HARTMAN : ORBINIIDAE, APISTOBRANCHIDAE, PARAONIDAE 217 



all other segments have biramous parapodia. In the thorax the parapodia 

 are lateral; they gradually ascend so that in middle and posterior seg- 

 ments of the abdomen they are dorsal. The body is broadest in the 

 middle thorax; it is slightly (Naineris and some species of Haploscolop- 

 los) to greatly depressed (Scoloplos (Leodamas) and some others). 

 Farther back it is cylindrical in cross section or somewhat flattened 

 dorsally. In some species or genera the ventrum of some anterior seg- 

 ments has transverse rows of fleshy lobes, collectively called ventral 

 fringe; otherwise the ventrum is smooth. 



Notopodia are more or less similar throughout the body except for 

 differences in size and relative proportions of parts. Each consists of a 

 simple, papillar or elongated lobe supported by one to several embedded 

 yellow rods or acicula. Each has a tuft of long, slender, distally pointed 

 setae ; in some segments, usually in posterior thoracic and anterior or all 

 abdominal segments, they may be accompanied by furcate or forked 

 setae (pi. 20, fig. 5). The postsetal lobe is more or less conspicuous; it 

 may be short and triangular or longer to cirriform (pi. 27, fig. 3) or it 

 may be foliaceous (pi. 22, fig. 1) or fringed; its shape is specific. It has 

 been variously called dorsal cirrus, branchia, secondary branchia, upper 

 cirrus, fleshy lobe, lancet-shaped lip, cirriform or dorsal languet, lanceo- 

 late lip, dorsal tubercle, cylindrical process and ligulate thread (see 

 Eisig, 1914, p. 174, for references). The name here used, postsetal lobe, 

 refers to its position behind the notopodial setal fascicle. 



The neuropodia are more highly modified and diversified within a 

 single individual than are the notopodia and thus more specific. In the 

 thorax the neuropodium is an oval or crescentic ridge and closely ap- 

 pressed to the body wall. A posterior or postsetal part may be a simple 

 fleshy ridge, or it may have one to several lobes along its margin, or there 

 may be a series of lobes forming a fringe (pi. 23, fig. 2). The prolonged 

 processes are called podial lobes if simple and fringe if multiple or 

 serrated. Thoracic neuropodia are provided with palisaded series of setae 

 or uncini or both. There are no embedded acicula. Abdominal neuro- 

 podia are slenderer, longer, and supported by one to several acicula 

 which may be entirely embedded or somewhat emergent ; the projecting 

 setae are generally in long, close tufts. 



Subpodial lobes or ventral cirri (if located immediately below the 

 neuropodium) are variable in occurrence and distribution. When present 

 they may be located at or near the ventral edge of abdominal and some 

 posterior thoracic neuropodia. Their presence and distribution or absence 

 is specific and has no generic significance. Thus in Phylo subpodial lobes 



