1905.] NATURAL SCIENCES OF PHILADELPHIA. 535 



the middle of the notopodial area and the ventral just behind the neuro- 

 podial tuft of setip. 



The branchiae are situated behind the palisade of notopodial setae, 

 beginning at the dorsal cirrus and extending fon\'ard around the ven- 

 tral border of the setae into the interramal area. Owing to the rela- 

 tively short notopodial setse the gills show distinctly and the body ap- 

 pears more depressed and has a dorsal aspect totally different from E. 

 bicirrata. Like E. heterobranchia and some other species the form of 

 the gills (fig. 16) varies greatly. A few near the ventral end of the 

 series are often quite simple and cirriform, and from this unbranched 

 form they vary to those with as many as 8 branches, the complexity 

 of the branching increasing with approximate regularity from the ven- 

 tral to the dorsal end of the series, except that the ventr almost gill 

 is usually much more branched than those immediately above it. The 

 following table shows the number of branches counted on segments 

 of the middle of the body of four specimens, the position of the three 

 cirri being indicated by their initial letters : 



D.C. 6, 8, 7, 7, 6, M.C. 6, 6, 6, 6, 4, 2, 3, 3, V.C. 



D.C. 7, 7, 6, 6, -, M.C. 5, 5, 4, 3, 1, 1, 5, -, V.C. 



D.C. 6, 5, 6, 5, 5, M.C. 5, 5, 4, 4, 1, 1, 6, -, V.C. 



D.C. 7, 6, 6, 5, -, M.C. 5, 5, 4, 3, 3, 2, 5, -, V.C. 



The 2 or 3 ventralmost gills occupy the space between the neuropodial 

 and notopodial setae, and it will be noticed that 4 or 5 lie dorsal and 

 7 or 8 ventral to the middle cirrus. The larger numbers are found 

 upon the larger and the smaller upon the smaller specimens, but it 

 seems probable from a comparison of the number of branches that both 

 divisions and coalescences of the ventral gills occur. Reduced numbers 

 are found also on a few segments at each end of the body. The 

 branches, which seldom arise upon a strictly dichotomous plan, spread 

 widely from a short trunk into a low bush-like form and terminate 

 without expansions in slender, tapering tips. 



All setae are white or colorless except at the extreme tips, which are 

 stained with sulphur yellow. All are translucent, very brittle and hol- 

 low, with their cavities filled with the usual granular contents. ^ The 

 notopodials are slightly longer than the gills and of two forms. Deeply 

 cleft, very strongly and extensively serrate setae (fig. 15) occur in the 

 middle rows of the palisade. The remaining rows have only stout 

 spurred setae (fig. 14) without serrations, and there are no deeply cleft 

 or bifid setae without serrations. The spur is always very short, though 

 the internal cavity is deeply bifurcate. Many of these set£e have the 

 middle part of the shaft encircled by many fine parallel canals situated 



