POLYCH.ETA FROM NORTH AMERICA. 785 



2. Uncini generally 6 or 7 teeth, the anterior one being the 



largest (figs. 202 & 203 Johnson, 9). 



3. Very large size (fig. 1) with numerous abdominal segments, 



30 to 54 branchiae and from 80 to 160 serrations on edge 

 of operculum. 



Numerous specimens from Departure Bay, Dodds Narrows, 

 and two from Puget Sound (Prof. Kincaid's collection). 



Isolated tubes are to be found attached to the undersides of 

 stones on rocky shores near extreme low-water mark, and small 

 colonies may be found above this level in rock-pools. 



In other places attached to rocks near low-water level the 

 masses of large white calcareous tubes are very striking — they 

 are thick and often finely ridged, the lower parts being much 

 intertwined, the free distal ends often overgrown with Polyzoa, 

 iSpirorbis, etc. 



The brilliant red colour on the branchial crown may involve 

 the whole of the gills and opei-culum, or these may be colourless 

 except for the tips, or they may be barred and mottled in a 

 large variety of ways. The remainder of the body is generally 

 yellowish. 



As regards collar, thoracic membrane, and operculum with its 

 tubercles, this species agrees very closely with &'. vermicularis, 

 so fully described by St.-Joseph (24. pp. 328-335). Johnson (9) 

 presumably has made it into a new species on account of its 

 very much greater size with corresponding greater number of 

 abdominal segments, branchife and serrations on operculum, 

 together with small difierences in the setse and uncini. He 

 cannot, I think, have examined many specimens, for he states 

 that the functional operculum is on the right side (9. p. 432). 

 The position of this in the genus Serpula may be right or left as 

 shown by Zeleny (27. p. 34), but out of 50 specimens that I 

 have examined 28 had it on the left, 21 on the right, and the 

 remaining specimen had one on each side. Consequently, when 

 he says that there are about 100 serrations on the edge of the 

 operculum, I cannot think that Bush (3) is justified in recording 

 this as a distinction between this species and S. splendens with 

 127 to 150 serrations. 



Moore (19) gives 140 for the one specimen of S. columbicma in 

 which he counted the serrations. In my specimens they vary 

 from about 80 to 160 — the number apparently increasing with 



Another distinction given by Bush is that there are in 

 *S'. columhiana " but . 250 abdominal segments in a length of 

 55 mm.," whereas Johnson says " 250 or more" (9. p. 432), and 

 she gives 313 as the number in a specimen of her so-called 

 jS'. splendens, of which she does not state the size, and 190 in a 

 specimen 35 mm. long. These figures speak for themselves I 

 think as creating nothing but confusion. In 15 of my specimens 

 the average number of abdominal segments was 236, including 79 

 in a specimen 10 mm. long, 142 in a specimen 41 mm. long, and 

 310 in one 81 mm, long. 



