360 PROCEEDINGS : BOSTON SOCIETY NATUR AL HISTORY. 
Dimensions. Height of colony, 10 ram.; length of hydrotheca, 
.7 mm.; length of internodes, .65 mm. 
The specimen which I place here was of very small size and 
without gonosomes. The only character, and this a small one, by 
which to distinguish it from the very wide-spread A. polyzonias y 
is the well-marked wrinkling on the adcauline side of the hydro¬ 
theca. 
Habitat. Attached to stone dredged in Townsend Harbor. 
23. Sertularella tricuspidata Alder. PL 4, figs. 21, 21a, 
21b, 21c. 
Trophosome. Stems slender, alternately branched or divided 
dichotomously, often bipinnate at the top, jointed above each caly- 
cle and twisted at intervals. The hydrothecae are distant, cylindri¬ 
cal, smooth, slightly expanded and everted above, and have a 
3-toothed aperture. 
Gonosome. The gonotheca is large, and strongly cross-ribbed, 
with a plain funnel-shaped aperture which arises from a bowl-like 
expansion. 
Dimensions. Height of colony, 35-40 mm.; length of hydro¬ 
theca, .4 mm ; diameter at top of hydro theca, .15 mm.; broadest 
diameter, .2 mm.; length of gonotheca, 1.6 mm. ; greatest diame¬ 
ter of gonotheca, .6 mm. ; length of internodes, .5 mm. 
Except for the expanded and slightly everted margin the Puget 
Sound form agrees perfectly with Hincks’s description of this 
species. The joints are very slightly marked and often difficult 
to see. 
Habitat. Port Townsend Bay, dredged in 15 fathoms of water, 
off Marrowstone. Previously reported from Iceland (Hincks) ; 
Greenland (Buck); Strait of Belle Isle (A. S. Packard, Jr.); 
Alaska (Clarke). 
24. Sertularella nodulosa sp. nov. PI. 5, figs. 29, 29 a, 
29b. 
Trophosome. Stems simple or slightly and irregularly branched, 
branches also irregularly subbranched, the latter arising immedi¬ 
ately below the hydrothecae. Hydrothecae large, smooth or slightly 
waved, with a slight bulge below and a taper at the extremity. 
The margin bears three teeth and a three-parted operculum. The 
joints are slightly oblique and hydrothecae are deeply inserted mid¬ 
way between them. The hydranth contracts with a peculiar fold 
which is highly characteristic. 
