784 MISS HELEX PIXELL ON 



47. Poljchfeta from the Pacitic Coast ol: North America. — 

 Part I. Serpulid.e,. with a Revised Table of Classi- 

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

 PiXELL, B.Sc, r.Z.8., Demonstrator of Zoology and 

 Reid Fellow, Bedford College, University of London. 



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



(Plates LXXXYII.-LXXXIX.*) 



Systematic: Ikpex. Page 



Apomatiis titiisii, sp. ii 787 



Frotiila 2>acijtca, sp. n 788 



Classitication of Sjyirorbis 792 



Frofolteospira, subgen. ii 798 



Spirorbis anihilateralis, sp. ii 796 



S. raceniosus, sp. n 799 



S. wedins, si^. \\ 800 



General Characteristics of the Famibj Sex'pulidfe. 



1. Tube calcareous, neai-ly always attached to rocks or other 



substratum for some part of its length. 



2. Generally one or more branchife on dorsal side terminated 



by an operculum. 



3. Thorax, generally provided with a thoracic membrane, 



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

 segments. 



4. Gland shields in thorax only. 



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

 Generic characteristics f : — 



1. Collar setiv of bnyonet-shape, with spines at base of blade. 



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



serr.'itions on maigin. 



3. X^ncini with only a few lai'ge teeth. 



1. Sektula columbiaxa Johnson (9), 1901. (PI. LXXXYII. 

 fig. 1.) 

 Serpula splendens Bush (3), 1905. 

 Serpula colwmhiana INIoore (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 bvietly the generic and specific 

 characteristics in every case. Such a procedure has not previously been adopted, so 

 far as I know, and it will, no doubt, in some cases be necessary 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 

 ditficulties. 



