404 THE ANNELIDA POLYCHAETA. 



in width, not so noticeably widening toward one end. Rounded at the ends. 



Body densely clothed with slender filaments forming a thick coat, as in 

 the other species. 



The neuropodial setae are pale brown, being a little darker than in bythin- 

 cola. Wliereas in the latter species the neuropodial setae are apparently of 

 nearly equal stoutness tliroughout the length of the body, in the present species 

 they become very much more slender caudad, the long anterior ones being 

 very much coarser than the most posterior ones. Most setae in the type are 

 broken off near the base; the longest anterior one, which is distally incomplete, is 

 in the present condition 44 mm. long, so that originally it must have approached 

 the body in length. Notopodials very fine and short, pale. 



Length, 55 mm.; greatest width, 22 mm. 



Locality. Galapagos: ofT Hood Island, 12 miles S. E. of Ripple Point. 

 Sta. 4649 (lat. 1° 35' S., long. 89° 30' W.). Depth 633 fms. Bottom of Ught 

 grey Globigerina ooze. Bottom temp. 39.5° F. 10 November, 1904. 



Stern ASPiDAE. 



These are highly specialized polychaetes, of very distinctive appearance. 

 The body is short, consisting in superficial appearance of 19-22 somites, but 

 morphologically, as judged by the number of fasciae of setae in the posterior 

 region, composed of thu-ty-one somites (*S. scutata Rietsch, Ann. sci. nat., 1882, 

 13, p. 7; Vijdevsky, Densk. Akad. wissen. Wien, 1882, 43, p. 35). Of these, 

 fifteen Ue in front of the ventral shield, a chai-acteristic double horny, but not 

 truly chitinous (Goodrich, Quart, journ. micr. sci., 1898, 40, p. 239) plate or 

 shield, from the edges of which radiate fasciae of long setae on the ventral sur- 

 face at the posterior end of the body. The first seven somites in the state of 

 repose are retractile. The integument in general is covered with numerous 

 fine, hair-hke papillae, which are typically more numerous and coarse caudad of 

 the seventh somite. The integument caudad of this somite is commonly also 

 longitudinally fm-rowed, or striate. To the surface adhere numerous, chiefly 

 sUicious, particles, much as in the FlabelUgeridae. 



The prostomium is a very small rounded lobe just over, or in front of, the 

 mouth. It bears neither eyes nor appendages. 



Peristomium, or first somite, without setae. 



The anus opens on a papilla above the ventral shield. 



On each side of and above the anal papilla are two dense bundles of long. 



