POLYCH^ETA SEDENTARIA OF THE FIRTH OF FORTH. 647 



dorsum of 5th and 6th setigerous somites ; lateral filaments on some somites 

 in front of these, annulations on the buccal somite. Lateral branchial filaments, 

 arising immediately above the base of the notopodia, Larger than C. borealis, 

 length 10-13 cm. and upwards, diameter 5 mm. 



Habits. — Found in similar localities to those described for C. cirratus, but 

 nearer low-water mark ; it also burrows more deeply than the latter species. 



As Johnston remarks, it is somewhat difficult to ascertain to which somite 

 the tentacular filaments belong. Eyes are not visible in preserved specimens, 

 but faint pigmented lines are to be seen on the cephalic lobe in the living 

 animal. The region in front of the 1st chsetiferous somite has the same 

 characters as in C cirratus. The origin of the lateral filaments is a constant 

 and marked character of this species. The colour is dark red. 



Chcetozone, Malmgren. 



Chcetozone, Malmgren, Ann. Polych., p. 206. 



This genus was established by Malmgren, in 1867, for the following single 

 species. The distinguishing character is the arrangement of the chsetae of the 

 posterior somites, in an extended linear transverse series, so that they almost 

 encircle the body. 



Chwtozone setosa, Malmgren. 



Chcetozone setosa, Malmgren, loc. cit. 



Speci/ic Characters. — Smaller than Cirratulus cirratus; only two tentacles 

 which are much thicker than the branchial filaments, and arise immediately in 

 front of the first pair of parapodia ; tentacles with same characters as those of 

 Cirratulus. Eyes wanting; anterior end of cephalic lobe acuminate; 6 annuli 

 in front of 1st pair of parapodia. Branchial filaments arising close to base 

 of notopodium, slightly behind it. Anterior pair of nephridia opening at 

 base of 1st pair of parapodia, extending back through 2 or 3 somites, and 

 visible to the unaided eye, on account of their brown granular appearance 

 (PI. XXXIX. fig. 11). 



Anatomy. — There are 3 glandular cords in the dorsal vessel, as in Cirratulus, 

 which are quite black, and very conspicuous in the living animal. The lateral 

 branchial filaments occur on some of the somites throughout the body, and 

 are not limited to a certain region, as in Dodecaceria. The chsetae are all long 

 and setaceous. 



Dodecaceria, Oersted. 



Dodecaceria, Oersted, Annul. Dan. Consp., p. 44. 



A genus also containing only a single species, the following: — 



