BAHAMA MEDUSA. 23 



nematocyst-bearing ones. There are twelve otocysts, and the manubrium is 

 liask-shaped. The gonads, which begin to develop upon the radial canals at 

 the four corners of the manubrium, have now migrated down the radial 

 canals, although they are still small and immature. 



Cubaia geophila, of Key West, is closely allied to C. aphrodite and may be 

 simply a variety of the latter. In C. geophila, however, we find none of the 

 magenta-purple pigment at the bases of the tentacles. The bell is flatter, and 

 the manubrium longer and more slender, and the edges of the radial canals, 

 over the gonads, display dark colored, scattered pigment granules. 



In C. aphrodite the gonads are developed upon the middle portions of 

 the radial canals, while in C. geophila tliey are found upon the outer (cen- 

 trifugal) halves of the canals. 



Olindias tenuis. 

 Figs. 60-52, Plate V; Figs. 53-59, Plate VI. 



Mature Medusa: Figs. 53, 54, 58, 59; Plate VI. Bell hemispherical, 

 35 mm. in diameter. Gelatinous substance quite rigid. 



There are about ninety tentacles. Thirty-two of these are straight, 

 about one-third as long as the bell-diameter, and arise from the sides of 

 the bell in a zone at a short distance above the margin. These tentacles 

 are besprinkled with wart-like clusters of nematocysts, and near their distal 

 ends on the aboral side one finds an elongate, pad-like cluster of nematocyst 

 cells, having a sucker-like appearance, although there is no evidence that it 

 actually functions as an organ of adhesion. (Fig. 57, Plate VI.) 



In addition to the short, straight tentacles there are about sixty others 

 which are very flexible, and are often seen coiled in close helices. When ex- 

 tended these tentacles are about four times as long as the bell-diameter. They 

 arise from the bell-margin below the zone of origin of the straight tentacles. 

 A powerful strand of longitudinal muscle fibres extends throughout the en- 

 tire length of the outer side of each of these velar tentacles, wliile half rings 

 of nematocysts are found at regular intervals upon their inner sides.* 

 (See Figs. 54,58). The tentacles are thus comparable in their structure to 

 the long ones of Physalia. They terminate in a knob-like cluster of nemato- 

 cysts, and upon their aboral sides near the distal end there is a flat pad-like 

 cluster composed of very elongate and thickly crowded ectodermal cells. 

 (Fig. 58a.) 



* According to Goto, 1903, similar rings are found on the outer sides of the velar tentacles in 

 Olindioides. 



