394 THE AMERICAN NATURALIST. [VoL. XXXV. 
2, d. americana Nutting. 
Similar to former, but usually from deeper water and apparently of 
exceedingly variable character. 
3, A. rugosa Nutting. 
Trophosome: Colony unbranched, attaining a height of six inches. 
Hydrocladia in verticils of six or eight, borne on stout processes of the 
stem and with proximal ends reinforced on the lower sides by a thickening 
of the perisarc. Internodes long and irregular, further subdivided by 
numerous irregularly disposed septal thickenings, which resemble joints, 
giving the appearance of many internodes, where in reality there is but one. 
Hydrothece small, short, cylindrical, and supported below by a thickening 
of the internode. 
Monastechas quadridens McCr. 
Trophosome : Colony subflabellate in form, dichotomously branched, 
attaining a height of about six inches. Stem not fascicled, with indistinct 
internodes and branching at irregular intervals, those bearing hydrocladia 
being divided into long internodes, each of which bears a hydrocladium at 
its distal upper side. Hydrothece large, campanulate. 
Gonosome : Gonangia sac-like, borne on short processes below hydro- 
theca, and each protected by a pair of nematophores. 
Habitat: Various stations along the North Atlantic coast, and from 
Marthas Vineyard southward. 
Schizotricha Allman. 
Hydrocladia pinnately disposed, often branching once or more. Two 
species come within the range of this synopsis. 
1, S. zenella Verrill. 
Trophosome: Colony branched dichotomously, attaining a height of 
about two inches. Stems clustered or fascicled, divided into alternately 
longer and shorter internodes, the latter bearing each a hydrotheca and a 
hydrocladium. Hydrocladium slender, often branched, proximal internodes 
short, and without hydrothece, which are subcylindrical. 
Gonosome : Gonangia of curved shape, tapering at base and gradually 
enlarged toward the distal end, somewhat resembling cornucopiz. 
Habitat : Gay Head, Vineyard Sound, New Haven, Greenport, R. I., 
Woods Holl, Vineyard Haven. 
