190 PROCEEDINGS OF THE ACADEMY OF [Vol. LXXV 



prominent. Ventral to the neuropodium are three or four small 

 detached papillae in a transverse row; and other still smaller 

 papillae continue the series behind and above the neuropodium. 

 On more caudal segments these papillae become greatly reduced. 



Neuropodial setae fascicles consist of three or four rather large 

 compound crochets (Plate XVII, figs. 5, 6) alternating with as 

 many much smaller straight or slightly curved simple pointed spines 

 (Plate XVII, fig. 7). Compound setae are nearly colorless, flat- , 

 tened and very finely striated; stem curved chiefly at the point of 

 emergence, beyond which it becomes widened to an unequally bifur- 

 cate end connected with the appendage by a thin, flexible mem- 

 brane; appendage tapered to a strongly hooked pointed tip, beneath 

 which is a peculiar thin, transparent, scale-like guard which projects 

 slightly beyond the main point, the whole having the bird's-beak 

 aspect of the setae of many Sigaleonidae. On anterior parapodia 

 the appendages are much longer and become gradually reduced 

 caudad, but throughout the body they are always longer propor- 

 tionally to the width than the one figured by v. Marenzeller for 

 A. validus. 



Notosetae are simple, very slender, straight and apparently 

 normally smooth capillaries, on most segments having a length 

 nearly equaling the diameter of the body. On a few of the anterior 

 segments only one or two occur in a fascicle but usually there are 

 4-6. 



Type only known, 104 segments, length 77 mm., maximum 

 diam. (XXX), 3 mm. 



Station 4430, off Santa Cruz Island, 197-281 fathoms, black sand. 



Dodecacaria pacifica Fewkes. 



Besides several pieces of rock, bearing populous colonies of tubes, 

 there are twenty-five extracted and well-preserved worms which 

 agree with specimens described from Monterey Bay. Some are 

 deep black throughout, others dark brown, either throughout, or 

 with the caudal end black. Usually the first five notocirral gills 

 are equally enlarged, the fifth sometimes somewhat smaller and 

 followed by from two to five (usually four) much shorter filaments. 

 One example is peculiar in that the first three pairs of gills are 

 enlarged, the fourth very small and the fifth and sixth again en- 

 larged. 



Although the rock to which they are attached is an impure 

 fossiliferous limestone easily and almost completely soluble in 

 HCL, the worms have actually excavated its surface very little. 

 They cover it to a depth of two or three inches with a solid mass 

 of intricately interlacing tubes, cemented together firmly and 

 forming rounded nodules, to the surface of which the tubes of 

 other annelids and various other sedentary animals are attached. 

 When the mass is broken it is found to consist exclusively of tubes 



