1909.] NATURAL SCIENCES OF PHILADELPHIA. 261 



tralmost being in a close transverse series beginning immediately 

 beneath the neuropodia. On XXIX the papillae become fewer and 

 less crowded and the next three segments bear only two or three 

 detached papillae on each side immediately beneath the neuropodia, 

 the median area being bare. 



Parapodia of the anterior region are lateral and consist of low sloping 

 neuropodial platforms, bearing palisades of four to six rows of setae 

 backed by a low postsetal fold. In the neighborhood of XV, where 

 they are largest, they are about twice as deep as long, but anteriorly 

 the depth diminishes until it scarcely exceeds the length, while behind 

 XV they gradually decrease in both length and depth and in the pec- 

 tinated region shift dorsad to assume the form characteristic of the 

 posterior region at about XXII. Notopodia of anterior region incon- 

 spicuous spreading tufts of sessile setae immediately dorsad of the 

 neuropodia. When fully changed, beginning at XXIV, the parapodia 

 of the posterior region are strictly dorsal, borne with the gills on a 

 transverse fold. Each ramus consists of an elevated setigerous tubercle 

 bearing a small erect tuft of slender capillary setae and, in the case 

 of the neuropodium, a postsetal lobe divided into a minute conical 

 ventral part connected by a membrane to the side of the segment, 

 and a larger somewhat foliaceous dorsal part, while the postsetal lobe 

 of the notopodium is slightly foliaceous, sublanceolate and abruptly 

 bent at the base where it embraces the setae tuft. The only change 

 caudad is an increasing prominence for a time of the parapodia and a 

 progressive increase in length and slenderness of the notopodial post- 

 setal lobes. 



Gills begin on XX as a pair of minute papillae situated on the dorsum 

 and well separated from the notopodia. They increase in length 

 gradually and are fully developed only on segments following the 

 pectinated region, where they increase correspondingly to the growth 

 of the parapodia, but alway rise above the notopodial lobes as erect, 

 slightly flattened, lanceolate and ciliated processes close to the median 

 line and united with the opposite member of the pair by a low 

 membrane. 



No color remaining. Proboscis unknown. 



Notopodial setae of anterior region in spreading tufts, rather short, 

 tapered, flexible, capillary, with conspicuous subannular cameration 

 and along one side a small oblique opening into each chamber (PI. VIII, 

 fig. 32). In the posterior region they are straighter, much longer, 

 more slender and erect, and associated with the capillary setae in the 

 ventral part of middle and posterior bundles are a few very delicate 



