278 THE ANNELIDA POLYCHAETA. 



the bases of these hmbate setae are the delicate, transparent, and inconspicuous 

 pectinate forms ; these are few in number and extend but little beyond the level 

 of the tips of the crochets in the segments where these are present ; the end- 

 piece of these is asynmietrically, narrowly cuneate in form, one edge being 

 prolonged. (Plate 51, fig. 4). The crochets in each parapodium where present 

 are two in number; each is stout, with the usual double curve, and is distally 

 bidentate ; of the teeth the apical or one on convex side of the neck is acute, 

 with sides nearly straight, or the inner side a little convex and the tip of tooth 

 slightly bent inward; the other is much stouter with sides similarly straight 

 and its apex on a level with that of the smaller one and its outer edge parallel 

 with that of the latter; the guards extend over and somewhat above the teeth. 

 (Plate 51, fig. 5). The crochets begin on the thirteenth somite (twelfth para- 

 podium). On the first and a few succeeding parapodia there are a few larger 

 setae of the hooded crochet-type ; these are moderately long and a little curved 

 distad; each is bidentate, a single smaller accessory tooth lying considerably 

 below the large, nearly erect, distal one; the guards are conspicuously prolonged, 

 each being slender and with a fine tip. (Plate 51, fig. 6). On the immediately 

 succeeding somites these crochets seem to be replaced by finely tipped, untoothed 

 setae. 



The maxillae are thin and mostly pale, dark pigment occurring on the bor- 

 ders adjacent to the suture between blade and carriers and that between the 

 halves of the latter in maxillae I, and along the dentigerous borders of the other 

 maxillae. Maxillae I have the carrier-plate narrowing from the anterior end 

 caudad, i.e., its posterior portion subtriangular, the caudal angle mesally 

 narrowly incised; each blade is conspicuously curved distally in the usual way, 

 and is broad proximally, but slender distally, where also it is somewhat darkened. 

 Maxilla II on the left side in a paratype has eight long, slender, acute, and more 

 or less retrorse teeth along its inner edge, the untoothed proximal edge short. 

 The unpaired plate, which lies close to this plate within and parallel to it, bears 

 nine similar teeth. The right maxillae II appears to bear the same number as 

 the left, eight, though it is broken in the preparation examined, and one or more 

 additional teeth may have been present. The left maxilla III bears four slender, 

 acute teeth, the right seven. Maxillae IV with a single tooth. (Plate 50, fig. 7). 

 The mandibles are comparatively small, thin, and delicate; the masticatory 

 plates are narrow and elongate, their anterior edges minutely crenulate but not 

 truly dentate, very oblique, their projections meeting mesally at an angle of about 

 forty-five degrees; the stems rather slender and short, diverging caudad. 



