220 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 15 



of anterior segments. On prebranchial segments they may occur at a 

 place corresponding to the base of the branchia; farther back they are in 

 front of or under the branchial base (Eisig, 1914, p. 249). 



Large epithelial glandular pouches are present only in species of 

 Phyh, located in posterior thoracic segments, one pair to a segment. 

 They open to the exterior, are lined with secretory cells and covered 

 with a spirally wound outer musculature. Their distribution corresponds 

 with that of the modified spines or spears (pi. 23, fig. 2). The aperture 

 is at the anterior side of the neuropodium and in front of the uppermost 

 modified spine; it is usually accompanied by a fleshy foliaceous or papil- 

 lar lobe. The pouches are oval or pyriform and have a groove along the 

 posterior side where the uppermost spine lies lengthwise along it. The 

 glands have been considered repugnatory (Claparede, 1870, p. 56, pi. 

 22, fig. lb) and thought to function in defense or offense (Claparede, 

 1873, pp. 137-138). Eisig (1914, p. 229) called them defense glands 

 ("Wehrdrusen") and considered them homologous with nephridia. 

 Soderstrom (1920, p. 86) identified similar structures in polydoriid 

 spionids and concluded that they are secretory, emitting a chitinized, 

 setal-like substance. 



Nephridia are paired, segmental structures visible externally as 

 small pores located on the lower posterior side of most or all abdominal 

 neuropodia and sometimes on some posterior thoracic segments. At 

 sexual maturity some are modified and function as gonopores (Mau, 

 1881, pi. 27). 



Ventral pads are tumid, glandular areas arising from the body wall 

 below the neuropodial bases of some abdominal segments. They are 

 padlike and conspicuous in species of Phylo, Orbinia and Haploscoloplos; 

 they are foliaceous in Scoloplos (pi. 30, fig. 2) and Scolaricia, to little 

 developed or inconspicuous in some other genera. At sexual maturity 

 they may enlarge and be filled with developing ova. 



The posterior end of the body usually terminates in segments dimin- 

 ishing in length and width. The pygidium in small and collarlike; it 

 has one to many pairs of short papillar to long filamentous processes 

 (pi. 22, fig. 2). The anus is terminal or only slightly dorsal. 



Setae and acicula are entirely simple and without articulation. Setae 

 are diversified and highly specific. All notopodia and neuropodia have 

 slender, distally pointed setae ("Pfriemborsten" of Eisig, 1914) ; the 

 shaft is cylindrical and smooth and the distal end is compressed like a 

 blade and provided with spinelets (seen in reflected light) ; it appears 

 camerated, canaliculated or fenestrated when seen with transmitted 



