242 BUSH 



lar being long, finely serrate, tapered blades with coarser fin-like bases. 

 Prince William Sound, at Orca, on Crucigera tubes. 



SPIRORBIS LINEATUS sp. nov. 



p1. XXXIX, fig. 29. 

 Type locality. — Sitka. 



Moderately thick yellowish tubes, roughened by growth lines, and 

 2, rarely 3, spiral threads varying in size and position in different indi- 

 viduals, form more or less regular sinistral coils with small central 

 cavity. Sometimes a thread defines the central cavity, and at other 

 times this apparently disappears and one defines an outer shoulder, the 

 median one being constant, the three rarely occurring together. 

 Associated with these are tubes on which the spiral lines are so feeble 

 as to be scarcely discernible. Immature tubes with 3 spiral lines were 

 at first taken to be worn examples of the small S. granulatus Linne, 

 on which the three spirals form conspicuous thin lamellae. 



Diameter 1.5 to 2 mm. ; height about i mm. 



The collar setae of both species are similar in form, being long, 

 tapered, finely serrate blades with spiny fin-like bases. 



Sitka, on a much-worn bivalve; and Prince William Sound, at 

 Orca, on Crucigera tubes. 



SPIRORBIS SIMILIS sp. nov. 



pi. XXIX, fig. 3, c; pi. xxxix, figs. 16, 31 ; p1. xl, figs. 9, 17, 18; 



pi. XLiii, figs. 27, 31. 



Type locality. — Prince William Sound. 



Dull, opaque, unsculptured, usually regularly coiled, somewhat flar- 

 ing, sinistral tubes with small central cavity, similar to those of S. 

 more hi. 



On examination of the animal, however, the operculum plate and 

 setae were found to be very different in form, the collar setae being 

 regularly tapered, finely serrate blades, with fine fin-like bases, similar 

 to those seen in S. lineaius., and the operculum, a brood-pouch filled 

 with eggs, protected by a flat calcareous plate with a small spreading 

 base and the usual ventral prolongation or supporting wall. 



Prince William Sound, at Virgin Bay and Orca, on Crucigera 

 tubes ; Sitka, on fragments of rock. 



SPIRORBIS VIOLACEUS Levinsen 1883. 

 p1. xli, figs. I, 2; pi. xLii, figs. 8-12. 

 Type locality. — Greenland. 



