ANTHOMKIHS.K l H'CAINVI I.I.I A. I CM 



narrow radial-canals. The velum is narrow. The stomach is globular with a constricted base, 

 but no peduncle. 4 simple, unbranched oral tentacles, each ending in a single nematocyst- 

 knob. 4 pairs ol gonads on the adradial sides of the stomach. Stomach light-yellow. ( jonads 

 and tentacle-bulbs orange-yellow. ( kelli dark-red. Straits of Gibraltar in March. This may 

 be a young form, the shape ot the bell and unbranched condition of the oral tentacles being 

 indications ot immaturity. 



Bougainvillia platygaster. 



Hippocrenr plalygasler, HAECKEL, 1879, Syst. tier Mi-ilusen, p. 91. 



Bell cubical, flat above. 12 mm. high, 12 mm. wide. The 4 radially placed, marginal 

 tentacle clusters arise from wide, triangular, basal swellings, which are wider than the inter- 

 radial spaces between them. Each basal swelling gives rise to 10 to 12 tentacles, which are 

 shorter than the bell-diameter. The tentacles arise in a single row from their basal bulbs. 

 Ocelli ( ?) Stomach flat and 4-sided. It is 4 times as wide as high, and without a peduncle. 

 The 4 short, oral tentacles branch dichotomously 3 or 4 times, giving 8 to 16 short, terminal 

 ramuli in each quadrant. The 4 wide, rectangular gonads are on the interradial sides of the 

 stomach. The stomach, gonads, and tentacle-bulbs are reddish-yellow. 



Atlantic Ocean, Cape Verde, and Canary Islands. 



Distinguished by the wide, triangular, basal bulbs of its marginal tentacles, and its short, 

 wide, 4-sided stomach. 



Bougainvillia xantha Hartlaub. 



Bougaim'illia \antlia, HARTLAUR, 1X97, Wissen. Meeresuntersuch. Kommis., Meere Kiel, Helgoland, Neue Folge, Bd. 2, p. 461, 

 taf. 15, fign. 2, 3; taf. l(ia, fig. 3; taf. l6i, fig. 19. 



Young medusa. Bell rounded, somewhat higher than wide, with thick gelatinous walls. 

 Height 4 or 5 mm. Bell-margin 4-sided. Each of the 4 radially situated, marginal tentacle- 

 bulbs gives rise to 9 or 10 tentacles, with small, indifferently developed, brownish-violet ocelli. 

 4 quite wide radial-canals. Manubnum small, with 4 branching oral tentacles longer than the 

 manubnum. The oral tentacles branch dichotomously about 4 times and each ends in about 

 16 nematocyst-knobs. These terminal branches of the oral tentacles are very short in com- 

 parison with the length of the main shaft of the tentacle. The 4 interradial gonads begin to 

 develop in specimens about 4 mm. wide. The tentacle-bulbs and stomach are light golden- 

 yellow to reddish in color. The interradial entodermal lamella is translucent greenish-yellow. 

 Common at Helgoland from March until the end ot June. No mature specimens have been 

 seen and the hydroid is unknown. It is closely allied to K. ftiiviJn and may be only a variety 

 of the latter form. It appears, however, to have more marginal tentacles in corresponding 

 stages of growth than is seen in R. flnviJn and there are slight color differences. 



Bougainvillia carolinensis Allman. 



Plate 16, figs. 7 tu 9; plate 17, fig. 7. 



Hifiporrfne tarolinfnsn, McCfiADV, 1857, Gynin. Charleston Harbor, p. hi, plate 10, figs. 8-10. 



Margelis carolinrnsis, AI.ASSIZ, I,., 1862, Cont. Nat. Hist. l ; . S., vol. 4, p. 544. Anssi/, A., 1865, North Amir. Acal., p. 156, 



tigs. 241-248. HAECKEL, 1879, Syst. iler Meilusen, p. 89. 

 Bou^ainl'illia ctirolinensis, AI.LMAN, 1871, Monog. Tubul. Hvdroids, p. 316. 



Hougiiimi/lia carolinensis, NUTTINC., 1901, Bull. U. S. Fish Commission (or 1X99, vol. 19, pp. 350, 376; figs. 5, 89.- HARCITT, 

 1904, Bull. I'. S. Bureau of Fisheries, vol. 24, p. 39, plate 2, fig. 4; 1901, American Naturalist, vol. ^, p. ^83, fig. 46. 



AJult nit'Jnsii (plate 17, fig. "). Bell dome-shaped and 4 mm. in height. Bell-walls, 

 especially at apex, very thick. There are 4 radially arranged clusters of marginal tentacles 

 that arise from 4 small, bulbous, basal swellings. 7 to g tentacles in each cluster. The longest 

 of these tentacles attain a length about equal to the bell-height. The tentacles are slender 

 and quite stiff, and their tips are usually curled downwards in a semicircle. A large ectoder- 

 mal ocellus is situated at the base of each tentacle upon the ventral (centripetal) side. The 

 velum is well developed. There are 4 straight, narrow, radial tubes. The manubrium is 

 long and narrow, and extends for about half the distance from the inner apex ot the bell- 

 cavity to the velar opening. Near its distal end it is somewhat wider than at its base. The 

 mouth part, however, is a simple, narrow tube. 4 oral tentacles arise from the 4 radial sides 



