194 PROCEEDINGS OF THE ACADEMY OF [Vol. LXXV 



gills developed, the anterior right one being by far the largest. 

 Except for the more delicate stem, the uncini' agree perfectly with 

 the North Pacific specimens previously described. 



Stations 4322, off Point La Jolla, 110 fathoms, green mud and 

 shells; 4461, off Point Pinos Lighthouse, 285-357 fathoms, green 

 mud; 4464, same locality, 36-51 fathoms, soft dark gray mud; 

 4475, same locality, 58-85 fathoms, soft green mud; 4485, off 

 Santa Cruz Lighthouse, 39-108 fathoms, soft green mud and sand; 

 4510, off Point Pinos Lighthouse, 91-184 fathoms, green mud; 4522, 

 same locality, 130-149 fathoms, gray sand and shells; 4523, same 

 locality, 75-108 fathoms, gray sand and shells; 4523, same locality 

 75-108 fathoms, soft dark mud. 



Pista disjuncta sp. nov. Plate XVII, flg. 9. 



The distinctive characteristics of this species are the large size 

 of the gills and especially the great distance separating those of 

 the two sides, and the reduced size of the second pair of cirri. 



Prostomium scarcely arched, being a nearly straight transverse 

 fold strongly reflexed ventrad at the sides to form conspicuous 

 lateral lobes, its free margin upturned as a somewhat frilled mem- 

 brane covering the bases of the tentacles which spring from a 

 thick fold. Tentacles mostly detached, but evidently more num- 

 erous that in P. hrevibranchiata (=fimbriata.) 



Peristomium a tumid lip ventrally, divided dorsally by a trans- 

 verse furrow into two rings; wings scarcely developed, the sides 

 being somewhat thickened, and connected with the lateral lobes of 

 the prostomium. 



Somite II is distinct all round, nowhere with glandular thick- 

 enings but somewhat tumid below, and bears a pair of small 

 wings at the neuropodial level. On each side, separated from each 

 other by a wide interval equal to about half the width of the seg- 

 ment is a slight forward projection bearing the first gill. Both 

 transversely and longitudinally. III is a considerably larger segment, 

 resembling II ventrally, but with the narrow distally rounded 

 lateral wings, which project stiffly outward and upward at a 

 higher level and larger than those on II, but decidedly smaller 

 than the corresponding part of P. hrevibranchiata and other species. 

 Immediately dorsad of each wing is a groove and above this a 

 glandular thickening continuing forward into the projection bearing 

 the gills which lie caudo-laterad of those on II. On the dorsum is 

 a large smooth interbranchial area as long as I and II combined. 

 This branchial and prebranchial region of the worm is distinctly 

 flattened, but beginning with IV the form is terete or nearly so. 

 Otherwise IV is similar to III, but the lateral wings are replaced 

 by narrow frills which closely resemble typical tori and bear setae 



