SABELLIDAE 187 



Remarks. This species is based on very poor material but it nevertheless appears to 

 be quite distinct from the other members of the genus. The first bristle-bearing segment 

 is the fifth and not the third as in O. Ungulatiis and O . japoniciis . Moreover, there are two 

 distinct kinds of thoracic bristle and only one is recorded for O. lingulatus and japoniciis. 



Family SABELLIDAE 



1. Pickaxe bristles present in the thoracic tori 

 Pickaxe bristles absent from the thoracic tori ... 



2. Spatulate bristles present in the thoracic notopods ... 

 No spatulate bristles in the thoracic notopods... 



3. An anal spout or gutter present... 

 No anal spout 



4. Thoracic dorsal bristles all of one type... 

 Thoracic dorsal bristles of two distinct types ... 



... 2 

 ... 3 



PotamiUa 



Sabella 



Euchone 



... 4 



Oridia 



Chone 



Genus Sabella, Linnaeus 



Branchiae not spiral, without dorsal processes or subterminal eyes. The branchial 

 filaments may or may not carry eye-spots. The collar is lobed. The first chaetiger has 

 winged bristles. The remaining thoracic chaetigers carry dorsal bristles with vdngs of 

 varying breadth and ventral avicular hooks and pickaxe bristles. The abdominal hooks 

 are also avicular and the abdominal bristles winged. 



Sabella oatesiana, Benham. 



Benham, 1927, p. 135, pi. iv, figs. 116-122. 

 Occurrence. St. WS 788 (4). 



Specific characters. There are no tubes with these specimens. The largest measures 

 44 mm. by 3 mm. for about 50 chaetigers. The gills are 12 mm. in length. On the gills 

 there are a number of scattered eye-spots varying widely in number and distribution 

 from individual to individual. In one specimen they form two fairly conspicuous 

 irregular bands and in another specimen at the other extreme two or three scattered 

 spots only can be found after careful searching. Minute eye-spots are also present be- 

 tween the rami of the feet in all chaetigers except the first and there are two groups of 

 spots on the pygidium. There are about 20 pairs of gills with slender tips free from 

 barbules. There is a palmar membrane extending for about one-fourth the length of the 

 gills. The pair of long subulate palps extends well beyond the end of the palmar mem- 

 brane. Dorsally the collar is widely open. It begins with the notopod of the second 

 chaetiger, is slightly incised ventro-laterally and forms a pair of rounded, backwardly 

 curving, ventral lappets. There are eight thoracic chaetigers. The first chaetiger has 

 winged bristles only. In the other thoracic segments there are winged bristles of two 

 types, the one long and the other shorter and with wider wings. The thoracic uncini are 

 avicular with the manubrium prominently rounded in front and curved posteriorly. 

 The main tooth has a crown of numerous denticles. The pickaxe bristles have a long 



D XII jj, 



