288 THE ANNELIDA POLYCHAETA. 



side and trifilamentous on the left ; in another it is undivided on the right and 

 bifilamentous on the left; and in the type it is bifilamentous on both sides, the 

 branchiae, as in the case of the first ones, clearly exceeding the notocirri. (Plate 

 47, fig. 10). The thu'd branchiae in the type are trifilamentous, but in two other 

 specimens examined are symmetrically bifilamentous. (Plate 47, fig. 11). The 

 fourth branchiae in the type have four filaments on the left and three on the 

 right, the branching being arborescent ; in two other specimens they are simply 

 bifurcate. In the type the fifth branchiae on the left side has three filaments, 

 on the right four, the branching arborescent as usual; in the other specimens 

 each branchia has three filaments. (Plate 48, fig. 1). In the type the sixth 

 branchia on the right side has four branches, the left one missing; a second 

 specimen has four filaments on the left and three on the right. The seventh 

 and eighth branchiae of the left side have three filaments, the right missing; 

 the ninth three on each side, the tenth and eleventh four. (Plate 48, fig. 2) . On 

 the left side in the type the twelfth left branchia has two filaments of which 

 one is much more elongate than the right, the thu-teenth thi-ee, of which the 

 middle one is greatly elongate, and, when laid back against the body passes 

 beyond the middle line of the dorsum. (Plate 48, fig. 3). The fourteenth also 

 three, with the middle one similarly elongated. The eight branchiae following 

 this are mostly similarly trifilamentous. The following ones are almost all 

 unifilamentous with the filament long, reaching or surpassing the middorsal 

 line or, when laid forward, as they seem to be normally, attaining the third and 

 sometimes the fourth preceding somite (Plate 48, fig. 4) ; caudad these decrease, 

 but in the last detected (fifty fourth somite) they are still decidedly longer than 

 the notopodium. 



The acicula in the anterior parapodia are slender, distally reduced to a 

 fine tip and scarcely as thick as the dorsal setae, and more slender than the 

 ventral setae; their tips scarcely protrude. In the posterior region the acicula 

 become stouter and the fine tips protrude as usual. (Plate 47, fig. 6). In the 

 first three pau's of parapodia the dorsal fascia are capillary, slenderly acuminate, 

 finely tipped, and not hmbate. The coarser ventral setae in these parapodia 

 are compound, the joint distinct and well toward the tip; in these the tip is 

 bidentate, the apical process or lobe is large and rounded, the subapical very 

 small, acute, and close to the apical lobe; farther proximad there is a slight 

 shoulder as in the preceding species; the membranous guards narrow distally 

 to a slender point and rise much above the upper lobe. (Plate 47, fig. 3) . Farther 

 caudad the dorsal setae become longer; they end distaUy, as usual, in a very 



