154 



BOUGAINVILLIA SUPERCILIARIS. 



pable of expansion and contraction. In Figs. 236, 237, which are some- 

 what older Medusas in different attitudes, the digestive cavity is well 



Fig. 233. 



Fig. 235. 



Fig. 234. 



Fig. 236. 



developed, and from the four corners of the actinostome bulge out four 

 club-shaped appendages, the first traces of the oral tentacles. There 



Fig. 238. 



Fig. 237. 



are two well-developed tentacles, which were at first a mere knob, with 

 distinct eye-specks. (Fig. 234.) The bell is quite thin at this stage, and 



Fig. 233. Ilydromedusarium of Bougainvillia superciliaris. 



Fig. 234. Young elongated Medusa. 



Fig. 235. Somewhat more advanced than Fig. 234. 



Fig. 236. Appearance a short time before separating from the stem, in a contracted state. 



Fig. 237. The same as Fig. 236, expanded. 



Fig. 238. Young Bougainvillia, immediately after its liberation from the Ilydromedusarium. 



