178 PERCY SLADEN TRUST EXPEDITION 



7. Cyt^is tetrastyla, Eschscholtz, 1829. 



Localities. North of Ohagos Archipelago, Surface (Temp. 82° F.). 18 May, 1905, D. 

 1 specimen. South of Saya de Malha Banks. 50 — fms. 4 Sept. 1905, m. 2 speci- 

 mens. North of Saya de Malha Banks, Surface {Temp. 77°— 80°F.). 8 Sept. 1905, n. 



I specimen. 



The specimens collected by the " Sealark " are not in good condition. The largest is 

 about 2 mm. in diameter. Its stomach is on a short peduncle and the mouth surrounded 

 with at least twelve capitate tentacles. The four perradial marginal tentacles are 

 internally pigmented with a very dark reddish colour along their whole length, and 

 covered with a very thick ectoderm. The specimens have a few medusa-buds upon the 

 stomach. The structure of the tentacles and the shape of the basal bulbs are similar to 

 those of Cytoeis herdmani. 



Some of the specimens reported upon by Vanhoffen were collected by the " Valdivia " 

 in the Indian Ocean, one station being north of Chagos. 



8. BouGAlNViLLiA FULVA, Agassiz and Mayer, 1899. 



Bougainvillia fulva, Agassiz and Mayer, 1899, p. 162, pi. 2, fig. 6; 1902, p. 145, pi. 2, fig. 8. 



Bougainvillia fulva, Maas, 1905, p. 10, Taf. 1, fig. 8, Taf. 2, figs. 9—10; 1906, p. 87, pi. 2, figs. 4—5. 



Bougainvillia fulva, Bigelow, 1909, p. 195, pi. 6, fig. 7, pi. 44, figs. 5 — 7. 



Bougainvillia fulva, Hartlaub, 1909, p. 448, Taf. 19, figs. 1 — 4. 



Bougainvillia fulva, Mayer, 1910, p. 160. 



Localities. Chagos Archipelago, Salomon Atoll. 180 — fms. 30 June, 1905, 0. 



II specimens. Amirante Isles, Desroches Atoll. 400 — fms. 16 Oct. 1905, mm. 

 1 specimen. 



Except for the contraction of the margin of the umbrella the specimens are in very 

 good condition. The smallest one measured 6 mm. in height and 4 mm. in width, and 

 the largest 13 mm. in height and 10 mm. in width. 



The umbrella is very thick, about as thick at the top as on the side. Its natural 

 shape is altered owing to the great contraction of the margin. The contraction produces 

 deep perradial furrows and interradial ridges or lobes which meet in the centre of the 

 umbrella opening and close it up completely. The specimen figured by Maas (1906, pi. 2, 

 fig. 5) resembles this very closely in the shape of the contracted umbrella, but the jelly 

 above the sub-umbrella cavity is thicker than in my specimens. 



The stomach varies considerably in shape. When empty and uncontracted it hangs 

 down as a thin cruciform sac, but when full of food it becomes nearly globular. The four 

 oral tentacles are dichotomously branched, four times in the smallest specimen and seven 

 times in the largest one. The gonads form swellings upon the wall of the stomach and 

 have the appearance of eight distinct sacs, isolated perradially and interradially. 



The marginal tentacles are more or less contracted, and are very small and slender 

 when compared with the size of the umbrella. In the smallest specimen there are twelve 

 tentacles on each compound bulb ; and fourteen on a bulb was the maximum number 

 counted in the largest specimen. An ocellus is situated on the inner side of every 



