244 BUSH 



forming a regularly coiled low spire with central cavity, fragile in tex- 

 ture in preservation, dull opaque, roughened by conspicuous growth 

 and occasional obscure spiral lines. As noted on page 241, they can- 

 not readily be separated from the tubes of S. incongruvs. Although 

 the specimens are imperfect, their animals more or less mutilated, the 

 following important characters could be ascertained : 



Branchiae 7- 



Operculum forming a somewhat cylindrical (imperfect) brood- 

 pouch of simple cell tissue, protected on the end by a thin calcareous 

 cap, but showing no indication of an internal (partition) wall found in 

 this organ in some of the eastern species. One was filled with par- 

 tially developed eggs ; the others had the pouch torn away, leaving the 

 basal expansion in one instance showing the formation of a new cal- 

 careous terminal plate (pi. xxxv, fig. 14) and in another a simple 

 covering of tissue. 



Large eggs, showing a nucleus and nucleolus when stained, were 

 in the posterior part of the body-cavity, and smaller ones were scat- 

 tered through the (10?) posterior segments. 



In the 3 thoracic segments the setae vary remarkably in form. In 

 the collar fascicle the superior ones have very broad, conspicuously 

 scalloped, tapered blades ; in the other fascicles they are so narrow as 

 to be scarcely distinguishable from the inferior capillary ones. 



SPIRORBIS COMPTUS sp. nov. 



Type locality. ? California. 



On a red alga from California, without definite locality, associated 

 with S. spirillum, is a small, dextral, yellowish species, usually form- 

 ing a low regular coil with small central cavity, often spreading around 

 the base in a thin layer, the surface roughened by conspicuous trans- 

 verse lines and three prominent spiral ridges, one defining the central 

 cavity, one median, and one around the outer shoulder ; in immature 

 examples the median one is usually the most prominent, the others be- 

 ing scarcely noticeable. 



Diameter 1.5 mm. ; height less than I mm. 



The animals were all much dried. In a small specimen the oper- 

 culum had a thin disk-like plate with an elongated, angular basal por- 

 tion. In an adult the operculum, filled with eggs, was protected by a 

 flat calcareous cap with long basal shield. 



The setae were similar to those found in S. rugatus; those of the 

 collar fascicle, simple tapered blades with serrate edges. 



