TUBULABIAE 



97 



free-swiniiiiiiig medusa which is usually borne on the hydrocaulus and 

 has 4 radial canals; mari>inal tentacles either sinule or in clusters, and 

 4 or S manubrial gonads : about 19 genera. 



Key to the genera of Bougainvilliidae here described : 



Oi Hydroid colony arborescent : medusa with tentacles in clusters. 

 &i Medusa with tentacles in 4 clusters, 

 t'l Medusa without short knobbed tentacles ; hydroid arborescent. 



1. BOUGAINVILLIA 



Co Medusa with a pair of short knobbed tentacles at each cluster. .5. Nemopsis 



&2 Medusa with tentacles in S clusters ; hydroid like Bougainvillia . . 4. Ratiikea 



Oj Hydroid colony with creeping hydrorhiza ; medusa with only 2 long tentacles. 



6i Four short oral lobes 2. Perigonimus 



62 Four long oral lobes 3. Stomotoca 





§r 





Fig, 156 — BoupninvilJta 

 caroUnensis (Hargitt) . 



1. Bougainvillia Lesson. Trophosome : col- 

 ony arborescent with a dense perisarc, hydranth 

 with conical hypostome. Gonosome: medusa 

 globular, with branching oral tentacles and 4 

 pairs at first and later 4 groups of marginal 

 tentacles: 20 species. 



B. carolinensis (McCrady) (Fig. 156). Col- 

 ony may be 25 em. high, usually 7 to 12 cm.; 

 hypostome conspicuous; tentacles about 12; 

 medusa with brick-red manu- 

 brium and black ocelli, 4 mm. 

 in diameter: Cape Cod and 

 southward; common on fucus, 

 piles, etc. 



B. superciliaris Agassiz (Fig. 157). Colony 5 cm. 

 high or less; hypostome inconspicuous; tentacles 15 to 

 20; medusa with j-ellowish manubrium and black ocelli, 

 10 mm. in diameter: Newport to Greenland; on fucus 

 and shells; Europe. 



2. Perigonimus Sars. Trophosome : colony branch- 

 ing a little and rising from a reticulated hydrorhiza 

 with a gelatinous perisarc and conical hypostome. 

 Gonosome: medusa with 2 or 4 marginal tentacles; no 

 ocelli : 10 species. 



P. jonesi Osborn and Hargitt. Hydroid colony, 10 



mm. high or less; hydranth with 16 tentacles; medusa 



hemispherical with an apical projection, 2 mm. high and broad, with 2 



long tentacles and 2 additional tentacular bulbs; manubrium short. 



Bougainvillia 



superciliaris 



(Agassiz). 



squarish, with 

 Harbor, L. I. 



4 oral lobes: 



spider crabs {Libinia) at Cold Spring 



