232 



BUSH 



The Serpula columhiana abundant in Puget Sound and extending 

 southward along the CaUfornia coast to Golden Gate is described by 

 Johnson (1901) as having more numerous branchiae (54 in each lobe) , 

 fewer serrations (100) on the margin of the operculum, and but 250 

 abdominal segments in a length of 55 mm., with a breadth of 7 mm. 

 on the thorax. 



Specimens collected by Dr. Coe in August, 1901, on the California 

 coast are supposed to be immature examples of this species. They 

 are without color in formalin, except one, which has two pink spots 

 at the base of the trumpet-shaped process, but when first received one 

 showed both red and orange bands on the branchiae. The larger has 

 20 pairs of well-developed branchiae, besides a few small ventral ones 

 having very short pinnae, and the operculum has no serrations on its 

 margin. An example of the Alaska species of similar size has 35 

 pairs of branchiae and 127 serrations on the margin of the operculum. 



Genus Crucigera Benedict 1886. 

 Type, Crucigera websteri Benedict. ^ 



The very small type species of this genus, a cotype specimen of 

 which, from 26 fathoms in the Gulf of Mexico, has been sent from 

 Washington, has four ' digital processes * at the base of the operculum, 

 the axis of which is continuous with that of its peduncle. The Alas- 

 kan species, however, have but 3, 2 of them combining, forming a 

 large, rounded, bilobed process, to which the abruptly contracted dis- 

 tal end of the peduncle is so attached that its axis is not continuous 

 with that of the operculum. Benedict describes the texture as ' cal- 

 careo- cartilaginous,' but the operculum of the northern species, after 

 soaking in potash solution, retains its form as a thin, transparent, chi- 

 tinous shell. The tube is ornamented on one side by three conspicu- 

 ous lamellar-like longitudinal carinae, and on the opposite side by faintly 

 indicated ridges. The thicker tubes of the northern forms show no 

 indication of such ornamentation. 



The operculum of Serpula zelandica Baird (1865), as shown in 

 the figure, has similar coarse, blunt serrations on the margin, but no 

 processes at its base, thus representing a transition between typical Ser- 

 pula and Crucigera^ and therefore referable to Scleras tyla Morch 

 1863. 



1 Proc. U. S. Nat. Mus., ix, p. 550, pi. xxi, figs. 24, 25 ; pi. xxii, figs. 26-30, 

 1886. 



