1923] NATURAL SCIENCES OF PHILADELPHIA 241 



of the ventral ranks of III to IX expanded distally into a narrowly- 

 elliptical plate tipped by a prominent mueron (Plate XVIII, fig. 41). 

 Thoracic tori bear a posterior series of avicular uncini and an anter- 

 ior series of pick-shaped seta>, 15-20 in each series. The former 

 (fig. 42) have small body, prominent breast, high, erect neck and 

 small head with reduced crest and straight, strongly decurved 

 beak. Pick-shaped setae are nearly as stout as the seta? of the dorsal 

 fascicles with slightly curved stems, widened and truncated o])liciuely 

 at the end which is striated and bears a small mueron in front. 

 The end is enclosed in a flattened hood produced in front into a 

 straight acute process. Abdominal setae form small tufts of ten 

 to twelve and are similar to the dorsal thoracic setae; broadly 

 bilimlmte but produced into long tapered acute points from which 

 the limbi are gradually lost. The uncini are generally a])out 15 

 and except that the beak is slightly smalh^r do not differ perceptibly 

 from those of thoracic segments. 



Station 4431, off Santa Rosa Island, 38-45 fathoms, green mud, 



coarse gray sand. /■ o r '^ - ^ ''*-"' ^ 



Sabella elegans Bush. 



Two anterior ends represent this species. Each gill consists of 

 twenty to twenty-one fully developed radicles in addition to three 

 or four rudimentary ones. They are whitish at the base and distal 

 end and are marked with five zones of reddish brown alternating 

 with white. From five to seven pairs of eyes are borne on each of 

 the ventral and three, one or none on the extreme dorsal filaments 

 all at the end of the most distal brown patch. 



A tube is 140 mm. long and slightly under 5 mm. in diameter, 

 mucocartilagenoid in consistency and very fragile, pale brown, 

 translucent and slightly encrusted with fine sand grains, etc. 



Station 4312, off Point Loma Lighthouse, 95-135 fathoms, fine 

 gray sand and rock. . \ 



/ Parasabella pallida sp. nov. 



Branchiie with low branchiophores slightly prolonged ventrally 

 but not spirally coiled. Padiolcs twelve on one, thirteen on the 

 other side, the most ventral al)Out one-half as long as dorsalmost, 

 entirely free with no connecting basal membrane whatever, slightly 

 flattened but not definitely squared on the outer face, rather thick 

 and coarse, slightly tapered, about one-fifth of the tip free from 

 barbs. Barbs relatively few, more widely separated than usual. 

 No eyes; no color whatever. 



Collar prominent, of two conspicuous halves, widely separated 

 dorsally and prolonged ventrally as a pair of narrow pointed lobes 

 which are in contact along their contiguous borders. 



