ANTHOMKDIS.E Uol (iAINVI I.I.IA . 171 



The medusa is distinguished by its thin-walled, almost spherical hell, its wide velum. 

 and its very long oral tentacles which branch only at their outer ends. The Mask-shaped 

 stomach and small size are also characteristic. On the whole it presents the appearance of 

 a degenerate torm. 



Bougainvillia rugosa Clarke. 



Plato 17, fig. 2.. 

 Bougainvillia rugosa, CLARKI., |88>, Mem. Huston Soc. Nat. Hist., vol. 3, p. 140, plate 8, figs. 11-14. 



) tniti^ ini-1/iisn (plate 17, tig. 2). Umbrella somewhat pynlorm. 12 marginal tentacles, $ 

 at the base ot each radial tube. Tentacles all of equal size. According to Clarke, ocelli air 

 developed only at the bases ot those 2 tentacles which are first and second as one passes 

 around the bell from left to right, but I found a specimen with 12 ocelli, one at the base nf 

 each tentacle. The velum is well developed. There are 4 straight, narrow, ladial tubes. 

 The manubrium is short and thick, and there are 4 short, unbranched, oial tentacles. 



H \drnid. The hydroid stock attains a height of 75 mm. There are numerous irregu- 

 larly arranged branches. Some of the branches which arise near the proximal end arc about as 

 long as the main stem, but most of them are short and delicate. The branches bear secondary 

 branches which give rise to 3 or 4 terminal ramuli. The hydroid is rooted by a creeping stolon. 

 The polypites are fusiform and are protected by an expansion ot the pensarc which bears a 

 number of annulations. There are 8 to 10 short tentacles. The medusa-buds are borne upon 

 the ultimate branches immediately below the proximal bases ot the polypites. I lie hydroid is 

 light-brown. 



It was found by Clarke, 1882, growing upon .//< \rnildluin at Hampton Roads, Virginia, 

 and in the southern parts of Chesapeake Bay. A medusa believed to be of this species was 

 found by me in Charleston Harbor, South Carolina, on December 17, 1904. 



Bougainvillia trinema. 



Margin trinemti, VON LKNDKNFELD, 1884, Proc. Linncan Soc. New South Wales, vol. 9, p. 918, platr 41, fig. i }. 



An immature medusa from Sydney Harbor, New South Wales, Australia. The bell is 

 oval, rounded, 2 to 3 mm. wide. There are only 3 tentacles in each of the 4 clusters of marginal 

 tentacles. These are about half as long as the bell-height. Each of the 4 oral tentacles ends 

 in 3 ( ?) small, equal branches about one-third as long as the shaft of the oral tentacle. Ento- 

 derm ot stomach and tentacle-bulbs dark yellow. This may possibly be the young of II. fulva 

 Agassiz and Mayer, 1899, but von Lendenfeld's description and figure are too imperfect to 

 determine this point. 



Bougainvillia frondosa Mayer. 



Plate 16, fig. 6. 

 Bougainvillia fronJosa, MAYER, 1900, Bull. Mus. Comp. Zool. at Harvard Collide, vol. 37, p. 41, fig. 5, plati- -,. 



The bell is higher than a hemisphere with relatively straight, vertical sides, and about 

 2 mm. high. There are 4 radially placed clusters of marginal tentacles, which are situated 

 upon bulbs at the ends of the 4 radial-canals. Each bulb gives rise to but 2 tentacles, so that 

 there are only 8 in all. There are no ocelli at the bases of the tentacles. The velum is narrow. 

 There are 4 straight, narrow radial-canals and a simple, narrow ring-canal. The manubrium 

 is cruciform in cross-section, short, thick, and flask-shaped. It extends about half the dis- 

 tance from the inner apex of the bell-cavity to the velar opening. There are 4 radially placed. 

 oral tentacles, each of which branches dichotomously 2 or 3 times. Planulx develop upon 

 the sides of the stomach near, and on both sides of, the 4 principal jadn. I at first consid- 

 ered these to be parasitic Zooxanthellae, but further studies have shown that they are pl.innl.i 

 Hartlaub, 1897, observes a similar phenomenon in Bougainvillia superciliarii, etc., and 

 Maas, 1904, cites it in (*.\t<m mgritinn (Result. Camp. Prince de Monaco, fasc. 28, p. 8. plate 

 i, tigs. 3, 4). 



The entoderm of the manubrium and tentacle-bulbs is pinkish-white and the tentacle tips 

 are turquoise. This medusa is occasionally found at Tortugas, Florida, in June to Julv. 



