2C>6 BUSH 



lower embedded portions, of a rusty brown color, much thinner above, 

 of a light horn color, sometimes tinged with wine color, covered with 

 a thin layer of fine gray sand, to which small hydroids, ascidians, and 

 seaweeds adhere ; within, sometimes beautifully iridescent or silvery. 



SCHIZOBRANCHIA INSIGNIS sp. nov. 



pi. xxiv, figs. 1,2; pi. xxvii, fig. i ; pi. xxvm, fig. 5 ; pi. xxxv, 

 figs. 2, 12, 13, 15, 16, 26, 27. 



Type locality. Yakutat. 



This large species is light brown in color, more or less tinged with 

 pink, with the branchiae sometimes of the same tone but usually of a 

 deep wine color. 



Segments short, flattened, numbering about 180 in the largest speci- 

 mens, of which 8 belong to the thorax ; in those of medium size the 

 number varies from 6 to 8. 



Branchiae stout at base, comparatively short, the larger portion of 

 them of nearly uniform length, measuring 17 mm. They are often ar- 

 ranged somewhat biserially, and number about 16 in the outer or 

 regular series ; in immature specimens the number often differs in the 

 two lobes. Each rachis is usually regularly dichotomously divided 

 from one to four times, so that there may be between 200 and 300 ter- 

 minal branches (occasionally one occurs which has three primary 

 divisions) ; the pinnae are long and slender, crowded distally, forming 

 very blunt, broadly rounded ends, which are often much twisted. 



Eyes large, numerous, irregularly placed on the back of most of the 

 rachises, principally along the posterior portion. 



Collar very deep at the sides, at the end of the slightly developed 

 dorsal lobes. 



Fascicles of setae in slightly oblique series on the thorax. 



Many of the specimens have eggs showing along the abdominal 

 tori. 



. Length of a perfect specimen about 158 mm., or 6.25 inches ; breadth 

 at base of collar about 7 mm. ; length of thorax along setae about 14 

 mm. A young, much contracted specimen has 18 pairs of branchiae, 

 all forked, the longest twice. It is about 5 mm. in breadth, and has 8 

 thoracic and 80 abdominal segments in a length of 37 mm. Another, 

 less contracted one, about 4 mm. broad, has 16 pairs of branchiae, 

 8 thoracic and 100 abdominal segments in a length of 75 mm. A 

 smaller one, about 3.5 mm. broad, has 18 pairs of simple branchiae, 8 

 thoracic and 50 abdominal segments in a length of about 20 mm. 



