208 BUSH 



SCHIZOBRANCHIA CONCINNA sp. nov. 



pi. xxni, figs. 2, 3; pl. xxvin, fig. 2 ; pi. xxxiv, figs. 15, 17, 18; 

 pi. xxxv, figs. 17, 24. 



Type locality. Orca, Prince William Sound. 



At Orca, with the preceding species ( S. nobilis) , the anterior por- 

 tion of a single specimen was found, which is remarkable for its slen- 

 der rounded form and long, unequal, very slender branchiae with their 

 numerous terminal branches, about 22 in each lobe, the long ones 

 about 30 mm. in length, often regularly forked 6 times, so that one 

 might have as many as 64 tips. The pinnae are long and very slender. 

 The eyes are numerous and very conspicuous, though varying in size, 

 often with a diagonal line of pigment. 



There are about 16 segments in a length of about 33 mm., 8 of 

 which belong to the thorax, which is about 7.5 mm. in breadth at base 

 of collar and 13 mm. in length along setae. 



Young, varying in size from n to over 50 mm. in length and .5 to 

 3 mm. in breadth, have 5 to 14 pairs of branchiae, 6 to 8 thoracic and 

 from 40 to over 60 abdominal segments. They differ from S. dubia 

 in having both body and branchiae tinged with delicate pink or wine 

 color and the setae and avicular uncini larger and more numerous. 



SCHIZOBRANCHIA DUBIA sp. nov. 



pl. xxvin, fig. i ; pl. xxix, fig. i ; pl. xxxni, fig. 7; pl. xxxvi, figs, i, 2, 3, 

 17, 18, 19, 20; pl. xxxvn, fig. 28. 



Type locality. Orca, Prince William Sound. 



This species bears a superficial resemblance to Pseudopotamilla 

 reniformis (Miiller) and P. oculifera Leidy, but differs in having 

 some of the branchiae forked. 



The slender tubes are found in closely crowded masses. 



The animals in preservation show but a slight tinge of brown on the 

 base of the branchiae, which are relatively long and slender, with long 

 graceful pinnae forming broadly rounded ends. Eyes very conspicuous. 



There is great irregularity in the development of the 40 or 50 speci- 

 mens examined. Among those of the same size, the larger number 

 have 6 and 7 thoracic segments on opposite sides, a few have 8, and 

 one has 9 ; in those differing in size this inconstancy is still more 

 marked. The smallest specimen, about 6 mm. long and i mm. broad, 

 has 8 thoracic and 25 abdominal segments, 5 pairs of branchiae, the 

 dorsal ones forked ; another, about 7 mm. long, has 8 thoracic and 

 about 50 abdominal segments, 7 pairs of branchiae ; another, 15 mm. 



