412 University of California Publications in Zoology [Vol.16 



the neurosetae are curved, with the tips slightly covered with hairs ; 

 in A. brevitentaculata the neurosetae are smooth, with the tips less 

 curved — almost straight. The elytra are granular in A. brevitentacu- 

 lata; they are thin and smooth in A. negligens. 



Description. — The body (pi. 37, fig. 84) is ovate, slightly arched 

 on the dorsum and slightly convex ventrally, i.e., the rest of the body 

 from the base of the parapodia is slightly elevated. The length of 

 the body is 23 mm. The width at the widest part of the body, between 

 segments 9 and 17, is 14 mm. from tip to tip of setae, 9 mm. be- 

 tween parapodia. The anterior end of the body is broadly rounded. 

 Towards the posterior portion the body width decreases very gradu- 

 ally, then attenuates abruptly before the last seven or eight segments 

 in a narrow caudal portion about 0.5 mm. in width. There are 

 thirty -five well-defined segments. The ventral surface is gray, thickly 

 covered with fine papillae varying in size. The dorsal papillae (pi. 

 35, fig. 58) are still smaller than the ventral, with capped tips. 



The prostomium (pi. 35, fig. 51) is slightly broader than it is long 

 and is attached to the peristomium by a long, narrow isthmus about 

 one-fourth of the width of the prostomium. The median tentacle is 

 short, bends upwards and ends in a bulbous tip. Each ocular promi- 

 nence bears a pair of large eyes which are slightly fused. The palpi 

 are stout, decreasing in diameter very gradually towards the distal 

 ends. They have a short basal portion, and are two and a half times 

 the length of the prostomium. They are smooth without any grooves 

 and are sparsely covered with minute sensory cilia, visible only under 

 high magnification. The facial caruncle is compressed between the 

 palpi, ending in a long finger-like projection that hangs over the 

 mouth ventrally. The mouth is situated ventralh', bounded by the 

 third segment, and the broad ventral lip is well marked off from the 

 rest of the body by deep grooves on each side of it. 



There are fifteen pairs of elytra (pi. 35, fig. 55) arranged in the 

 usual order. They are attached to the body by long elytrophores, and 

 are covered with fine papillae and brown incrustations. 



The branchiae (pi. 35, fig. 59) begin at tlie sixtii segment, occur- 

 ring thence on all cirriferous segments to the thirtieth. As usual, the 

 anterior and posterior ones are smaller and less developed, those 

 toward the center of the body are broad, each having 8 to 11 simple, 

 finger-like projections. 



The parapodia (pi. 35, fig. 61) are comparatively short, biramous, 

 and supported by two aciculi. The neuropodium is of the u.sual shape 



