SABELLIDES AND SERPULIDES 



209 



long, has 6 and 7 thoracic and 50 abdominal segments and 8 pairs of 

 branchiiE ; among the largest specimens, 67 mm. long and 2.5 mm. 

 broad, one has 7 thoracic and 115 abdominal segments and 14 pairs of 

 branchiae, and another has 8 thoracic segments and 15 pairs of branchiae. 

 There is also great diversity in the number of branchiae which become 

 forked. 



The short tori and small fascicles of setae forming straight series along 

 the sides of the body, and the inferior spatulate setae usually arranged 

 in two parallel rows, appear to be constant in character. 



Numerous specimens of a similar slender form collected at Dutch 

 Harbor, Unalaska Island, differ in their relatively shorter, stouter, more 

 divided branchiae and in the greater number and size of their setae and 

 avicular uncini, which agree in form with those of S. nobilis, 



SCHIZOBRANCHIA AFFINIS sp. nov. 

 p1. XXXIII, figs. 9, II, 17, 23 ; p1. XXXV, fig. 9. 

 Type locality, — Popof Island. 



Two small crimson or wine-colored specimens appear to have little 

 affinity with those of similar size belonging to other species. They 

 are immature, as only one has the longest dorsal branchiae forked ; and 

 as they are said to have been dredged, they are probably the young 

 of some shallow- water form. 



They are about 3 mm. in breadth, and have from 13 to 16 pairs of 

 branchiae about 7 mm. in length, which have long, rather stout, regu- 

 larly developed pinnae and a few conspicuous eyes. In both specimens 

 posterior segments are wanting. One has 9 thoracic and 35 abdom- 

 inal segments in a length of 27 mm., and the other has 8 thoracic and 

 20 abdominal segments, with well-developed eggs showing along 

 their tori, in a length of 28 mm. 



Genus Eudistylia nov. 



Type, Erdistylia gigantea sp. nov. 



Like Distylia of Quatrefages (1865), this genus has the branchial 

 lobes equal and spirally coiled, forming more or less elongated, per- 

 manent spires, differing in this character from typical Sabella and 

 other genera which have the branchial lobes attached but a portion of 

 their length, the more or less prolonged ventral portion being free 

 and spirally twisted or involute in retraction, flaring in expansion 

 (p1. XXVI, fig. 2) . Dorsal ends protected or stiffened by a conspicuous, 

 usually white, thin edge. 



