32 UNITED STATES NATIONAL MUSEUM BULLETIN 251 



side of thorax ; some dorsal muscles ratlier fine. Stigmatal rows 8-11 ; 

 anus opens at level of sixth or seventh transverse vessel. Ciliated 

 groove a small oval opening. Stomach situated near middle of abdo- 

 m.en ; with 10-15 longitudinal plications on surface, excluding typhlo- 

 solis. Proximal portion of rectum swollen conspicuously, possibly 

 forming a pair of caeca when animal is alive and fully extended. 

 Postabdomen considerably long, filled with yellowish-orange mesen- 

 chyme cells in most zooids, except for those colonies from Otaru. In 

 these, 23 testicular follicles arranged roughly in two rows in an exam- 

 ined zooid. 



Trunk of larvae elongated, 550/a long or 620ju,X340/a in specimens 

 examined. Three disc-shaped attachment processes arranged lineally. 

 Sixteen pairs of small ampullae in anterior half of trunk. Sensory 

 organ situated at level of posterior one-third, two pigment flecks ar- 

 ranged anteroposteriorly. Larval test granulated. 



Remarks. — Colonies encrusted and impregnated with sand grains 

 closely resemble A. constrictmn Sluiter from tropical waters, as stated 

 later. 



7. Amaroucium pUciferum Redlkorzev 



Figure 6 



Amaroucium pUciferum Redikorzev, 1927, p. 387, figs. 9-10. — Tokioka, 1953a, 

 p. 183, pi. 6, fig.s. 1-10 ; pi. 7, fig. 1. 



MATERIAL EXAMINED 



Hawaiian Islands: Auau Channel between Maui and Lanai; Alba- 

 tross sta. 3875. One colony surrounding branch of coralline algae 

 (USNM 11735). 



Description. — Colony roughly cylindrical in form, 30 mm. in 

 length, 13-14 mm. in diameter. Test gelatinous, rather hard, milky 

 white and opaque. Surface marked with many irregularly arranged 

 grooves, but quite free of any foreign matter. Several common cloacal 

 apertures openmg at the bottom of grooves, zooids also open in the 

 grooves. External appearance clearly shows that colony is strongly 

 contracted. Atrial languet projecting from middle of area between 

 dorsal ganglion and atrial aperture (fig. Qb) ; tip of languet simple or 

 bifid. Stigmatal rows 13-15, with about a dozen stigmata in each 

 row. Ciliated groove a small, oval opening. Stomach slightly ante- 

 rior to middle of abdomen, about two-thirds as long as contracted 

 thorax; longitudinal plications on surface 18-23, including typhlosolis. 

 One pair of caeca at proximal end of rectum. Postabdomen rather 

 thin and very long, being 1.5 to 3 times the length of thorax and ab- 

 domen, or even longer in some zooids. Testicular follicles numerous, 

 usually 50-60, arranged roughly in two rows; they may be flattened 

 anteroposteriorly, as shown in figure 6c, when packed compactly in 



