110 CCELENTEBATA 



S. gracillima (G. 0. Sars) (Fig. 181). Colony about 5 cm. high; 

 branches divided into regular internodes, each bearing a hydrocladium : 

 New England coast; Europe. 



4. CLADOCARPITS Allman. Colony usually branched; hydrocladia 

 not branched ; gonangia borne on the stem at the base of the hydrocladia 

 and protected by special branchlets armed with nematophores : 15 

 American species. 



C. flexilis Verrill (Fig. 182). Colony up to 20 cm. long and slender; 

 hydrotheca long and cylindrical, lying close to the hydrocladium; pro- 

 tecting branchlets of the gonangia branched like deer's horns: in moder- 

 ately deep water along the Atlantic coast; common. 



FAMILY 3. CAMPANULABIIDAE. 



Trophosome: either a branched or simple colony on which are bell- 

 shaped and usually stalked hydrothecae; hypostome trumpet-shaped. 

 Gonosome: gonangium large, the blastostyle producing planulae and 

 never free medusae: about 33 genera. 



Key to the genera of Campanulariidae here described: 



! Hydrotheca rudimentary, the hydranth not being entirely retracted 



into it 1. HALECIUM 



o,Hydrotheca not rudimentary. 



6 a Blastostyle does not project from the gonangium. 

 <?! Stem not completely annulated. 



cfi Gonangium without acrocyst, colony not parasitic 2. CAMPANULABIA 



<1 3 Gonangium with acrocyst ; colony parasitic on other hydroids, etc. 



3. CALYCELLA 



c 2 Stem completely annulated 4. OPERCULABELLA 



ft, Blastostyle projects from the gonangium 5. GONOTHYREA 



1. HALECIUM Oken. Branching colonies with creeping hydrorhiza; 

 the hydrothecae are more or less rudimentary, being shallow and 

 disc-like or funnel-shaped, the margin often with a circle of dots, 

 into which the hydranths can be only partially retracted: numerous 

 species. 



H. halecinum (L.) (Fig. 183). Colony 10 to 20 cm. high, rigid; 

 hydrothecae alternate on the stem, cylindrical, often annulated; gonan- 

 gia appear in a row, the male gonangium slender and club-shaped, the 

 female rather irregular in shape with broad distal end and a terminal 

 aperture: New Jersey to Labrador; in shallow water; Puget Sound to 

 Alaska; Europe. 



2. CAMPANULARIA Lamouroux. Colony either branched or simple, 

 with bell-shaped hydrothecae, which are without operculum, and with 

 or without marginal teeth: many species. 



