ECHINODEKMATA OF NEW ENGLAND. 37 



membranous, pointed, produced. Hydranths with webbed 



tentacles. 



C. acuminata. 



Leptoscyphus. Stem simple or branching, attached by 

 a thread-like stolon. Hydrothecae with operculum com- 

 posed of convergent segments. Hydranths cylindrical 

 with medusiform zooids. 



Medusa, Lizzia grata ? 



Lafoza. Stem simple, creeping tubular fibre, or erect 

 and composed of many aggregated tubes rooted by a fili- 

 form stolon. Hydrothecse tubular, sessile or with a short 

 pedicel. No operculum. Hydranths cylindrical with con- 

 ical proboscis. 



L. robusta. 



Cahjcella. Stem a creeping tubular fibre, erect, com- 

 pound branched, rooted by a filiform stolon. Hydrothecre 

 tubular with an operculum formed of convergent segments 

 or a plaited membrane. Hydranths cylindrical with coni- 

 cal proboscis. Fixed sporosacs. 1 



O. humilis. 

 B 



Solatia (Grammaria Stimpson). Stem erect, com- 

 posed of aggregate tubes, branching rooted. Hydrothecas 

 cylindrical, sessile, no operculum, aclnate for part of length. 

 Disposed on all sides of the stem in regular and equidis- 

 tant longitudinal series. 



S. robusta. 



Filelliim. Stem creeping, filiform, reticulate, im- 

 mersed in chitinous crust. Hydrothecse tubular, decum- 

 bent, adherent. No operculum, irregularly arranged 

 along the stem to which they are attached by short stalk. 



Sertularella. Plant-like. Stem branching, jointed, 



1 Sacs in which the spores are contained; gonosac, sac containing the male 

 sexual elements. 



