398 PROCEEDINGS OF THE ACADEMY OF [April, 



and appendages of intermediate length. Setae composing the outer 

 ventral arc are very slender with smooth (or anteriorly slightly spinu- 

 lose), rather strongly curved shafts and appendages with the number 

 of joints increasing from one on ventral to seven or eight on the most 

 dorsal and anterior setae and varying correspondingly in length. 

 These have the tips conspicuously hooked and bifid (fig. 118). Two 

 stout dark-colored setae with short unjointed strongly hooked and 

 bifid appendages (fig. 119) occur about the middle of the posterior 

 row regularly on parapodia behind XXX. On the cotype one of these 

 was found on V but none could be detected on other anterior parapodia. 

 Proceeding caudally all articulated setae tend to have fewer joints. 



Elytra occur on II, IV, V and alternate segments to XXVII and 

 after that on every consecutive segment to the end of the piece. They 

 are thin, only moderately arched and in the type devoid of pigment, 

 though anterior ones of the cotype are each marked with a short 

 curved dusky bar near the median border ; posteriorly most of them are 

 covered with a light ferruginous deposit. They are of the usual broadly 

 lunate form (Pi. XXXIII. fig. 114), becoming narrower behind XXVII, 

 truncate laterally where they are fimbriated with rather sparse but 

 moderately long processes, often arranged in small groups with minute 

 papillae between (fig. 1156). The elliptical scar lies laterad of the 

 middle, the third of the elytron external to its outer edge being note- 

 worthy for its rich supply of branching nerves and the absence of 

 surface nodules except for a narrow area adjacent to the umbilicus. 

 The remainder of the surface is thickly studded with small hard 

 trihedral nodules or spines, becoming slightly larger toward the 

 posterior border (fig. 115a). 



Stations 4,343, south of South Coronada Island, vicinity of San 

 Diego, 55-155 fathoms, fine gray sand (type); 4,552, off Point Pinos 

 Light-house, Monterey Bay, 66-73 fathoms, green mud and rocks 

 (two cotypes). 



This species resembles Sthenelais blanchardi Kinberg, of the coast 

 of Chile, in having all of the compound neuropodial setae bifid at the 

 tips, but differs in having those of the ventral group much less slender 

 and with fewer articulations than figured by Kinberg, the median 

 tentacle relatively longer and the smooth lateral area of the elytra 

 decidedly broader. 



Explanation of Plates XXVIII-XXXIII. 



Unless stated otherwise., all figures are drawn, with aid of the camera 

 lucida, from the types. 



