784 MISS HELEN PIXELL ON 



47. Polychiieta from the Pacific Coast ol: North America. — 

 Part I. Seepulid^, with a Revised Table of Classi- 

 fication of the Genus Spirorhis. By Helen L. M. 

 PiXELL, B.Sc, F.Z.S., Demonstrator of Zoology and 

 Reid Fellow, Bedford College, University of London. 



[Received May 6, 1912 : Read June 4, 1912.] 



(Plates LXXXVII.-LXXXIX.*) 



S3'stematic : Index. Page 



Apomattis timsii, sp. u 787 



Frotida joacifica, sp. n 788 



Classification of Spirorhis 792 



Protol(sospira, subgen. n 798 



Spirorhis anihilatercdis , sp. n 796 



S. racemosus, sp. n : 799 



S. medius, sp. n 800 



General Characteristics of the Family Serpulidse. 



1. Tube calcareous, nearly always attached to rocks or other 



substratum for some part of its length. 



2. Generally one or more branchise on dorsal side terminated 



by an operculum. 



3. Thorax, generally provided with a thoracic membi-ane, 



representing the fused cirri and having 3-9 (usually 7) 

 segments. 



4. Gland shields in thoi^ax only. 



Genus Serpula Linne (13) 1767, Philippi (21) 1844. 

 Generic characteristics t : — - 



1. Collar setee of bayonet-shape, with spines at base of blade. 



2. Operculum funnel-shaped, with numerous radii ending in 



serrations on margin. 



3. Uncini with only a few large teeth. 



1. Serpula Columbiana Johnson (9), 1901. (PI. LXXXVII. 

 %• 1-) 

 Serpida sjilendens Bush (3), 1905. 

 Serpula columbiana Moore (19), 1909. 



Specific characteristics : — 



1. Anterior abdominal setfe with flaring fringed ends, short 



and deeply embedded, posteriorly replaced by small fascicles 



of very long stiff spines. 



* For explanation of the Plates see p. 805. 



t An attempt is here made to summarise briefly the generic and specific 

 characteristics in everjr case. Such a procedure has not previouslj' been adopted, so 

 far as I know, and it will, no doubt, in some cases be necessarj' at some future time 

 to modify such characteristics, but in the present confused state of our systematic 

 knowledge of the Serpulids, this seems to be a course likely to eliminate some of the 

 difficulties. 



