POLyCII.l^/rA FROM XORXri AMERICA, 789 



Three specimens from Fairway Channel outside Departui-e Bay- 

 in about 30 fathoms ; one from Puget Sound (Prof. Kincaid's 

 collection). No tube. 



The specimens were colourless except for the branchiae, which 

 appear greenish due to the contained blood. Down the outer 

 side of each branchial rachis was a line of opaque white spots. 



The branchial crown (10-15 mm. high) easily falls off, leaving a 

 scar ; the remainder of the body is 38 to 60 mm. long, rather more 

 than one-third of which is thorax. This is broad and flattened 

 with nearly parallel sides (&g. 5 a) and the usual 7 setigerous 

 segments. The thoracic membrane is very wide, with an entii-e 

 margin which can extend beyond the setae but is generally 

 considerably crumpled. The collar is notched in the median 

 ventral line and has a deep fissure on each side. The inward 

 coil of the stout base of the branchial crown is seen on the right 

 side of the specimen in fig. 5 a. It takes 1^ to 2 turns inwards 

 and upwards, the short inner gills reaching about the same 

 height as the outer long ones. An interbranchial membrane 

 connects the lower third of the gills, of which there are about 

 60 pairs having small closely placed pinnse almost to their 

 extremities. At the junction of the branchiae with the stout 

 basal membrane which carries them there is a slight ridge 

 visible externally, and at this place on the inner side arises 

 the oral membrane, which is continuous across the median line 

 and up each of the spirals. On the dorsal side of the mouth is 

 another shorter membranous lip. 



Uncini begin on the third setigerous segment. They have the 

 characteristic shape (fig. 5f). The first two millimetres or so of 

 the abdomen is achaetous, nearly round, and of smaller diameter 

 than the wide dorso-ventrally depressed part which follows. 

 The ventral surface has deep segmental grooves showing 83-110 

 segments, and a wide faecal groove which turns to the right on 

 reaching the thorax. Laterally the short tori are -i-aised on 

 distinct parapodial processes which extend to the posterior end 

 of the body. The last 30 or so segments on the dorsal surface 

 are covered with the calcareous-looking gland which anteriorly 

 tapers off to two points, suggesting a paired origin. 



In section the gland is seen to occupy nearly the whole 

 thickness of the dorsal body-wall, the longitudinal muscles being- 

 pushed towards the sides. Nearly all the cells are crowded with 

 the spherical granules or globules which stain easily with iron 

 haematoxylin, and are apparently similar to those in the glandulai- 

 cells so frequently found in the epidermis. 



This hind region of the abdomen has very long setae which 

 extend 2 mm. or more on each side but are easily broken. At 

 first sight they appear to be simjjle spines very slightly bent at 

 the extremities, but, with high magnification, a narrow striated 

 wing may be made out (fig. 5 e), shorter seta? found with these 

 are more distinctly winged (fig. 5 d). The other abdominal 

 segments have ventral fascicles containing about 13 short, stout, 



Proc. Zoou Soc— 1912, No. LIII. .53 



