No. 413.] WORTH-AMERICAN INVERTEBRATES. 395 
2, S. gracillama Sars. (FIG. 31). 
Trophosome: Stem sparingly branched, having a height of about two 
inches and somewhat fascicled. Branches divided into regular internodes, 
each of which bears a hydrocladium on a short, stout process near its distal 
. Hydrocladia alternate, branching 
dichotomously twice or more beyond its 
proximal internode. Hydrothe- 
cæ small, cup-shaped. 
Gonosome : Gonangia borne 
in pairs on the stems in the 
axils of the hydrocladia, and 
also at the forks of the latter, 
cylindrical in shape, tapering at 
proximal ends, sessile. 
Habitat: Shallower waters, 
New England coast. 
Cladocarpus Allman. 
Stem simple or fascicled. 
Hydrothece deep and with 
smooth margins or with lateral 
'sinuations, and with one or two 
anterior teeth. A single species 
comes within the range of this 
synopsis. 
Fic. 31. Fic. 32. 
Fic. 31. — ScAizotricha gracillima Sars. Branched 
hydrocladium (enlarged). (After Nutting.) 
Fic. 32. — Cladocarpus flexilis Verrill. Portion of C. flexilis Verrill (Fic. 32). 
ydrocladium (enlarged). (After Nutting.) 
Trophosome: Colony long, 
slender, sparsely branching, stem not fascicled, attaining a height of about 
nine inches. Hydrocladia distinct, slightly sinuous, divided into rather 
slender internodes, each with a number of septal ridges back of hydrothecæ, 
which are deep, tubular, nearly straight, and with a single anterior tooth at 
the aperture. 
Gonosome : Gonangia numerous, borne on stem and bases of hydro- 
cladia, oblong-ovate, with latero-terminal orifice. 
