362 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
5. Selaginopsis group. 
27. Selaginopsis cylindrica Clarke. PI. 3, figs. 17, 17 a. 
Thujaria cylindrica Clarke. 
The hydrocaulus is erect, simple, stout, gradually tapering from 
the distal end to the base, and divided by oblique joints into 
internodes of variable length; 3-4 annulations at the base, regularly 
branched; branches alternately arranged, cylindrical or polygonal 
in section. The hydrothecae are tubular, almost entirely imbedded, 
tapering at extremity and curved slightly outwards. Aperture 
oval. Hydrothecae on stem arranged in six longitudinal rows in 
such a manner that the appearance of oblique transverse rows is 
given. Gonophores not known. 
Dimensions. Length of main stem, about 45 mm.; length of 
branches, 18 mm.; length of hydrotheca, .45 mm.; greatest diam¬ 
eter of liydrotlieca, 2 mm. 
Habitat. Dredged with Aglaophenia in Townsend BaA". 
Reported from Alaska (Clarke). 
6. Ily dr allmania group. 
28. Hydrallmania falcata Linn. PI. 5, figs. 25, 25a, 25b. 
The stems are fairly stout, not flexuous ; destitute of calycles,, 
Avith 3-4 plain rings about the base. The branches are alternate, 
distant, regularly pinnate, and given off above each joint. The 
hydrothecae, 3-4 to each internode, are tubular, closely appressed,. 
slightly tapering toAvards the margin, and are turned alternately 
toAvards the right and left. Joints oblique. Aperture plain. 
Gonothecae (ITincks) ovate, tapering below with a slightly tubu¬ 
lar neck. 
T) intensions. Height of stem, 25-30 mm.; length of hydro¬ 
theca, .45 mm.; greatest diameter, .2 mm.; length of internodes on 
stem, 1.5-2 mm. 
Habitat. Port Townsend Bay. Not common. 
Plumulariidae. 
29. Flumularia setacea. PI. 5, figs. 27, 27 a, 27b, 27c. 
Trophosome. The shoots are delicate, and the stem is slightly 
Avaved and regularly jointed. Pinnae alternate, one to each inter- 
