POLYCHAETOUS ANNELIDS COLLECTED AT FRIDAY 

 HARBOR, STATE OF WASHINGTON, IN FEBRUARY 



AND MARCH 1920. 



By a. L. Tread well. 



The following is a partial report of the results of an investigation 

 on the Pacific annelids, conducted during the season of 1920 under 

 the auspices of the Department of Marine Biology of the Carnegie 

 Institution of Washington, Dr. A. G. Mayor, Director. It com- 

 prises descriptions of certain new species of polychaetes collected by 

 the writer in the vicinity of Friday Harbor, State of Washington, in 

 February and early March 1920, with notes on some previously 

 described. Grateful acknowledgment is made to Professor T. C. 

 Frye, Director of the Puget Sound Biological Station, who put the 

 resources of his laboratory at my disposal. 



FamUy SYLLID^. 



Autolytus varius Treadwell. 



Auiolytus varius Treadwell. 1914, New Syllidae from San Francisco Bay, collected by 

 the U. S. S. Albatross. Univ. of Calif. Pub. in Zoology, vol. 13, No. 9, page 237, 

 figs. 4 to 7. 



The original description was taken from a single preserved specimen. The first 

 ones obtained in 1920 were collected by Mr. J. Little in the herring trap near the ship- 

 yard at Friday Harbor and were swimming at the surface. Later, others were found 

 in the same locality. The anterior end (fig. 1) agreed in structure with the original 

 description, except that the tentacular cirri are more nearly equal to the antennae 

 in size than was there stated. The palps are very small, are directed ventrally, and 

 are not visible from the dorsal surface. They are fused for more than half their length, 

 the free portion being in the form of a blunt cone. The smaller eyes (black) are shown 

 as lying directly over the (stippled) larger ones. The first five somites are not very 

 sharply marked off from one another, but two sets of longitudinal lines extend along the 

 dorsal surfaces of somites 1 to 4. The inner ones mark off median areas which are suc- 

 cessively wider from before backward. Lateral to each is a fainter line running parallel 

 to it. These areas are very clearly outlined, but not much elevated above the general 

 surface. The natatory setae are excessively deUcate and are blunt-ended, though the 

 end may turn sUghtly so as to be seen in profile, and then look as if sharp-pointed. 

 Behind the brood pouch are 60 or more somites gradually narrowing toward the py- 

 gidium and with successively smaller cirri. There are two anal cirri larger than the 

 dorsal cirri immediately in front of them. The animals vary greatly in size, for while 

 most were 30 mm. long, one of only 10 nam. was carrying a brood pouch with young. 



In the living animals are two color phases: (1) Light green body-color with a white 

 brood-sac containing eggs in cleavage stages. The coloration is most intense through 

 the median body-region, and is there most marked as a dark-green line crossing each 

 somite toward its posterior end, continued on to the posterior face of the parapodium 

 to the point of attachment of the dorsal cirrus and covering the basal joint of the cirrus. 

 The distal part of the cirrus is white. (2) The color varies through shades of reddish 

 brown, the brood-sac being bright salmon. In these the brood-sacs contained 

 larvae. This color difference is quite independent of the color of the larvffi them- 



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