222 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 15 



Modified spines or spears are found only in Phylo, in posterior 

 thoracic neuropodia. They form a single row in front of other setae. 

 The uppermost one (pi. 23, fig. 2) is near the aperture of the glandular 

 pouch and may project from the parapodium for a considerable distance. 

 Farther down they are increasingly embedded in parapodial tissue. Re- 

 placement of upper or most worn ones is progressively from below. Ac- 

 cording to the species, the color of the spine varies from pale yellow to 

 very dark or black. In shape they are acicular (pi. 24, fig. 2) or spear- 

 like (pi. 23, fig. 4) or hastate to sagittate. Their position at the sides of 

 a long, otherwise unarmed body suggests that they function in the stabili- 

 zation or equilibration of the animal. 



Brush-tipped setae (pi. 42, fig. 2) are known only in Califia (see 

 below) ; they are, essentially, modified pointed setae in which the in- 

 ternal fibrils are freed to form a broomlike distal end. Pseuduncini or 

 false hooks are delicate spines with a soft dark tip, associated with 

 glandular pouches in Phylo ; they are small and slender and thus easily 

 overlooked. Flails ("Geiselpfriemen" of Eisig, 1914) are modified 

 pointed setae abruptly bent in their distal part; they occur only in ab- 

 dominal neuropodia of Scolaricia. 



Acicula or embedded supporting rods occur in all notopodia and 

 abdominal neuropodia. In most genera they are in bundles of two or 

 more; in Scoloplos (Leodamas) abdominal neuropodia have single thick, 

 distally curved acicula that project from the parapodial lobe (pi. 32, 

 fig. 2). 



Generic limitations are not rigid, because of the high degree of 

 reticulation of most morphological features. This has resulted in an 

 interchangeable use of generic and subgeneric categories, as Scoloplos for 

 Naineris, or Aricia including Phylo. The number of thoracic segments 

 varies but is fairly constant specifically in Phylo and Orbinia; it is in- 

 constant in Naineris. The presence of podial and subpodial papillae and 

 interramal cirri and the distribution of branchiae can be used only 

 specifically. The approximate shape of the prostomium varies with the 

 age of individuals but is more or less constant in adult individuals, unless 

 the proboscis is everted. 



Podial and subpodial lobes are most highly developed in Orbinia and 

 Phylo ; their distribution and number are fairly specific. The occurrence 

 and distribution of other processes named above are to be examined with 

 the same caution. 



Thoracic neuropodia are thick and semilunar to oval; they have 

 transverse rows of podial fringe in some species of Orbinia and Phylo ; 

 they are less modified in species of other genera and least so in Naineris 





