i63 DISCOVERY REPORTS 



Polydora natrix, Soderstrom. 



Soderstrom, 1920, p. 254, figs. 165 and 166, with synonymy. 



Polydora polybranchia, Fauvel, nee Haswell, 1916, p. 441, pi. viii, figs. 13-20. 



Occurrence. St. WS 27 (i). 



Specific characters. The single specimen measures about 10 mm. for 55 chaetigers. 

 The prostomium is divided in front into two lobes by a median groove and is continued 

 backwards as a narrow, laterally compressed crest as far as the 2nd chaetiger. 



The I St chaetiger carries dorsal as well as ventral bristles. The first branchia appears 

 on the 2nd chaetiger and branchiae are continued to within about a dozen segments from 

 the end of the body. The hooks begin on the 7th chaetiger. The modified 5th chaetiger 

 carries two rows of large characteristic bristles. The anterior row consists of giant 

 bristles with cup-shaped tips. These cups have a rugose surface and at one place the rim 

 is raised to a low point. The posterior row consists of acicular bristles with hooked tips. 



Remarks. There are several records of this species from South America and the 

 Falkland Islands under the name of Polydora polybranchia, Haswell. Fauvel in 1916 

 pointed out that this form differed from polybranchia in the possession of dorsal bristles 

 in the ist foot, a difference which led Soderstrom to establish it under a separate specific 

 name. 



Family CHAETOPTERIDAE 

 Genus Chaetopterus, Cuvier 



Body large and stout, divided into three distinct regions. An anterior region with 

 uniramous feet, paddle-shaped bristles and special modified bristles in the 4th foot. 

 Middle region of five biramous segments, the first carrying a pair of wing-like ap- 

 pendages, the second with the dorsal ramus modified into a rounded sucker-like organ, 

 the remaining dorsal rami fan-shaped. The ventral rami are lamellar, coalescent and 

 carry rows of uncini. The hinder region has biramous feet, the dorsal rami being 

 cylindrical and the ventral bilobed and uncinigerous. Tube horny or parchment-like. 



Chaetopterus variopedatus (Renier). 

 Fauvel, 1927, p. 77, fig. 26 a-n. 



Occurrence. St. WS 583 (6); WS 837 (i). 



Specific characters. As there appears to be only one species, the specific characters 

 are those of the genus. 



Family CHLORHAEMIDAE 



Body enveloped in a sheath of mucus Flabelligera 



No mucous sheath Stylarioides 



Genus Stylarioides, Delle Chiaje 

 Body elongated, cylindrical, sometimes tapering posteriorly into a kind of tail. The 

 surface is papillated. Two large palps; gills filiform, borne on a retractile stalk. Bristles 

 of the first few chaetigers directed forwards to form the cephalic cage. Dorsal bristles 



