496 PROCEEDINGS OF THE ACADEMY OF [July, 



That is described as having from 13-16 spines on the operculum,, 

 which are figured as having bulbous bases not at all like the simple 

 taper of the Bermuda species. The tube is given as slightly tortuous, 

 loosely agglomerate, with unequal lines of growth; 3 mm. in diameter. 

 Another related species (E. benzoni Morch, 1863) is recorded from Bahia, 

 Brazil. This builds left-handed, solitary, very solid, obsoletely nodulose 

 spirorbiform tubes attached to Purpura and Dolium. 



Hydroides bispinosa sp. nov. 



Two specimens differ from typical Hydroides in having the edge of 

 the lower cup of the operculum, with broad, shallow scallops, not deep 

 narrow points; the upper cup has about 9 strongly curved, tapered 

 spines somewhat angular on the outer side with a single small pointed 

 process or spinelet on each side just below the angle and a long spike- 

 like spinule on inner base. Rudimentary operculum in opposite 

 lobe. Branchiae eight on each side; long, rather stout, with very long 

 terminal filament. Thoracic membrane but little (comparatively)' 

 developed, with moderately deep collar. Seta? in collar fascicle with 

 two very prominent striated spines at base of abruptly tapered ends ; 

 in the following six fascicles long tapered blades. Uncini noticeable 

 in being triangular, broad at base, with few, about equal, very sharply 

 pointed, much curved, well separated, teeth, 5 or 6 on those of thorax 

 and 3 or 4 on abdomen. Abdominal setae in fascicles of seven, flaring 

 without elongation, the edge coarsely dentate, one end tooth larger 

 than the others and curved in hook-shape; similar to the setae figured 

 by Marenzeller as Hydroides multispinosa ; additional long stiff hair- 

 like ones along caudal region. 



Tubes much roughened by irregular growth lines crossing two large 

 dorsal carinae, the shallow central area extending forward at the 

 aperture in a broadly rounded projection; attached in irregular flat 

 coils in masses or groups, often much eroded. 



Hydroides parvus (Treadwell 1901, as Eupomatus). 



Numerous rough tubes of good size, variously curved and often 

 twisted over each other, are attached their entire length to the exposed 

 surface of valves of Placuanimia rudis, the interior of the aperture of 

 Livona pica and other hosts found at Bermuda. 



They are rounded, of nearly uniform diameter, with two more or 

 less clearly defined dorsal carinae, with here and there a faintly indicated 

 median thread; no transverse markings other than irregular ones of 

 growth which roughen the entire surface. 



The species was recorded by Treadwell from the shores of Porto Rico 



