BAHAMA MEDUS.^. 11 
mentary teiitacle-bnlbs. This is one of the most abundant medusae at the 
Bahamas in summer. 
Bougainvillia Niobe, Mayer. 
Figs. U-ldc, Plate II. 
Mayer, A. G., 1894 ; Bull. Mus. Comp. Zool. at Harvard Coll., Vol. XXV. p. 236, PI. I, Fig. 2; 
Ibid. Vol. XXXVII, p. 43. 
Adult Medusa, Fig. 14. Bell 6.75 mm. high and 4.8 mm. in diameter, with 
vertical sides and thick gelatinous walls. Four radially situated clusters of 
marginal tentacles, each composed of about eight tentacles about as long as 
the bell height. On the lower side of each tentacle near the bulbous base 
there is a dark-colored ocellus. Four straight, narrow, radial canals. Manu- 
brium wide, flask-shaped, and cruciform in cross section. About one-half as 
long as the height of the bell-cavity. Four radially situated clusters of oral 
tentacles, each of which branches dichotomously four times. These are very 
flexible, and their distal ends are knobbed. 
Medusa buds arise from the eight adradii of the manubrium (Fig. 15) ; the 
youngest buds being immediately under and on both sides of the point of 
entrance of each radial canal, while older ones are found farther down the 
sides of the manubrium. The youngest buds (Fig. 15% Plate II) were small 
ovoid vesicles contained entirely in the ectoderm. The limiting mend)rane, si, 
between the entoderm and ectoderm of the manubrium, in the neighborhood 
of these buds, was entire, and I could find no evidence of cells passing through 
it. Indeed, throughout the future development of the buds the entoderm re 
mained inert and its limiting membrane unbroken. The wall of the vesicle 
consisted of two layers of cells; an outer epithelium of ectodermal cells, 
c V t. h., destined to give rise to the ectoderm of the bud, and an inner layer 
of somewhat larger cells destined to give rise to the entoderm of the budding 
medusa, e n t. h., Fig 15^. These latter cells, it will be observed, are entirely 
encased by the ectoderm of the manubrium. They may, however, have been 
derived at an earlier stage from the entoderm, and have migrated into the 
ectoderm. Careful search has, however, failed to reveal evidence of any such 
migration, and in default of evidence to the contrary, we assume that these 
cells may be ectodenual in origin, although destined to produce the entoderm 
of the bud. 
The central cavity of the vesicle is partially filled Avith a loose mass of 
