434 PROCEEDINGS OF THE ACADEMY OF [June, 



and so continue, with occasional variations to three divisions, to 

 XXII on one side, and XXIII on the other, then again trifid to 

 XXVII, bifid, or occasionally trifid. to XXXII; from this point a single 

 filament, which is at first larger than, but gradually decreases until it 

 only equals, the dorsal cirrus, continues to the posterior end of the 

 piece. Although the same bifurcate mode of l^ranching as in E. quin- 

 quifida occurs, the aspect of the gills is totally different; the branches 

 are thicker, stiffer and, instead of bending toward the middle, stand 

 erect, but the parapodia are placed so low down that they scarcely 

 arise above the level of the back. 



Setae fewer than in E. rnucronata, generally stouter and more regu- 

 larly arranged in horizontal rows. All are colorless. 



Compound setse with shafts thickened gradually at the end for a 

 distance considerably exceeding the length of the appendix, here with 

 strongly marked oblique striations and the dorsal margin distinctly 

 denticulated over a considerable distance; appendix short, the length 

 4-6 times its width, with a well-marked subterminal constriction and 

 a bifid tip, the terminal tooth slightly hooked, the other broad, straight, 

 acute; guard broad, without mucronate tip, closely following outline of 

 terminal tooth, beyond which it extends slightly on the dorsal side. 

 As usual the appendages are relatively longer on anterior and shorter 

 on posterior parapodia. 



Capillary setse about j longer than the compound, rather strongly 

 curved, and tapering only in the terminal § of the exposed portion, 

 but then to an excessively acute point. 



Spatulate or paddle-shaped setse rather more than h length of capil- 

 lary setse, by which they are concealed from above; situated caudad 

 of the acicula and ventrad of the capillary setse, tapering gently to 

 little expanded ends which have about nine points, both marginals 

 being produced, but very unec{ually, the anterior one apparently always 

 the longer. 



The acicula are deep brown, practically black, in color, and opaque 

 except at the smaller ends ; the ordinary ones are two in number, sub- 

 equal, bluntly tapered, and slightly curved at the end. In the posterior 

 somites, beginning at about XL. is a single ventral uncinate aciculum 

 of rather strongly sigmoid curvature and with a bifid hooked end. 

 They are always thickly incrusted with a reddish-ocherous deposit, 

 the removal of which destroys the guards. 



Jaws hoary brown, the thin plates yellow; maxillae stout, strongly 

 hooked and curved ventrad near the broad base, which is provided 

 with a prominent tubercle for muscular attachment; carrier broad, not 



