Vou. 2] Torrey.—Hydroids of the San Diego Region. 39 
opposite sides of the stem, one to each internode, having their origin in 
a small shoulder-like process just below each joint, divided usually into 
regular internodes, though in some cases, short internodes occur hetween 
the longer ones. Hydrothecae arranged uniserially, usually one to each 
internode, partly adherent to the stem, or entirely free, shallow, tapering 
slightly to the base, with an entire rim.’’ (Clark). 
Gonosome. Gonangia borne on the shoulder processes supporting 
the hydrocladia. Immature ones alone known; widest distally, tapering 
abruptly to base. 
Distribution. San Diego, 15 to 25 fathoms. Cape Etolin, 
Al., 8 to 10 fathoms (Clark). 
43. Plumularia setacea (Ellis). 
Corallina setacea, Ellis, 1755, p. 19. 
Plumularia setacea, Lamarck, 1816, p. 129. _ 
Plumularia setacea, Hincks, 1868, p. 296, pl. 66, fig. 1. 
Plumularia setacea, Clark, 1876a, p. 261, pl. 41, figs. 1, 2. 
Plumularia setacea, Nutting, 1900, p. 56, pl. 1, figs. 1-4. 
Plumularia palmeri, Nutting, 1900, p. 65, pl. 6, figs. 4, 5; 1901, 
p- 188. 
Plumularia setacea, Torrey, 1902, p. 79, pl. 11, fig. 105. 
Trophosome. Stems 5 to 100 mm. long, non-fascicled, divided into 
internodes, each bearing a hydrocladium from a distal process. Hydro-- 
eladia alternate; basal internode short, non-thecate; thecate and non- 
thecate internodes alternate; there may or may not be septal ridges at 
either end of each internode and associated with the hydrothecae. Latter 
not deeper than broad, broadest at margin. Nematophores polythalamic, 
2 supra and 1 infra-calyeine, 1 on each non-thecate internode except the 
basal internode of each hydrocladium, 2 on each cauline internode, 1 on 
the side opposite the hydrocladium, the other axillary. 
Gonosome. Gonangia borne on the stem near the axils of the hydro- 
cladia, much elongated, female somewhat longer and stouter than the 
male, with a long, narrow neck; small terminal aperture. 
Distribution. Pt. Loma, La Jolla, Catalina I., San Pedro, 
and Monterey, Cal. Victoria, B. C., Santa Barbara and San 
Diego (Nutting). Eastern U. S. (Nutting). Coasts of Europe 
and Gt. Britain (Hineks). Helgoland (Hartlaub). 
