No. 413.] WORTH-AMERICAN INVERTEBRATES. 387 
1, L. dumosa Flem. (Fic. 23). 
Trophosome: Stem creeping, sometimes erect and fascicled ; hydrothece 
tubular, margins devoid of teeth or operculum, usually sessile. 
Gonosome: (?) 
2, Z. calcarata A. Ag. (FIG. 24). 
Trophosome: Stems creeping, simple; hydrothecz tubular, sessile. 
Gonosome: Gonangia large, elongate, obovate or oblong, somewhat 
resembling those of certain campanula- 
Meduse large, transparent, with 
Fic. at Trope donet Pe (After Hin 
Fic. A. Ag yir bon A. Agassiz.) 
gonads suspended in folds beneath the radial canals; marginal tentacles 
numerous in mature specimens, only two when first set free. 
Habitat: Usually parasitic upon sertularian hydroids. 
3, LZ. pygmea Alder. 
Trophosome: Stem creeping; — minute, tubular, elongate, 
borne on very — annulated pedice 
Gonosome : (? 
Habitat: Parasitic on various hydroids. 
HALECIDA. 
Of this family a single genus comes within the range of this synopsis : 
namely, the type genus, Halecium (Oken), the characters of which may be 
Summarized as follows: 
Trophosome : Colony more or less branched, attached by a creeping 
hydrorhiza, Hydrotheca often shallow and disk-like, or funnel-shaped 
(hydrophores). In many species with double or triple margins due to 
