MAYER: MEDUSAE FROM THE TORTUGAS, FLORIDA. 41 



Dysmorphosa minuta, uov. sp. 



Fig. 43, Plate 18. 



Specific Characters. — The medusa is extremely minute, the bell being only 

 0.3 mm. in height. It is pear-shaped and the walls are quite thick. The ge- 

 latinous substance is remarkably delicate, and the medusa soon contracts into 

 a shapeless mass in captivity. There are 8 marginal tentacles, with well- 

 developed basal bulbs. The velum is small. There are 4 straight, slender 

 radial canals and a narrow circular vessel. The proboscis possesses a distinct 

 peduncle. The gastric portion as well as the peduncle is 4-sided in cross- 

 section. 4 well-developed oral tentacles surround the mouth, one being situated 

 at each radial corner. Each of these tentacles terminates in a knob-shaped 

 distal end, which is thickly covered with nematocysts. The entodermal cells 

 of the oral tentacles are disk-shaped and highly vacuolated. Several medusa 

 buds in various stages of development are found upon the upper interradial 

 regions of the gastric portion of the proboscis. In some specimens the ento- 

 derm of the proboscis and tentacle bulbs is turquoise blue, and in others lilac. 

 The medusa was common at the Tortugas, Florida, in the middle of July, 

 1898. It is the smallest hydro medusa known. Its color is also very different 

 from D. fulgurans, A. Agassiz, of Newport Harbor. 



BOUGAINVILLIA, Lesson, 1836. 

 Bougainvillia frondosa, nov. sp. 



Fig. 5, Plate 3. 



Specific Cliaracters. — The bell is dome-shaped and about 2 mm. in height. 

 There are 4 bunches of marginal tentacles, which are situated at the bases of the 

 4 radial canals. Each tentacle bulb gives rise to but 2 tentacles, thus making 

 8 in all. There are no ocelli at the bases of the tentacles. The velum is 

 small. There are 4 straight, simple, radial tubes. The proboscis is short, 

 thick, and flask-shaped, and extends only about one half of the distance from 

 the inner apex of the bell cavity to the velar opening. There are 4 radially 

 situated oral tentacles, each of which branches dichotomously two or three 

 times. The mature gonads are found in 4 radially situated swollen regions 

 upon the ectoderm of the proboscis, above the origins of the oral tentacles. 

 There are a number of flask-shaped bodies with narrow necks protruding from 

 the surface of the proboscis in the region of the gonads. Each of these flask- 

 shaped capsules is filled with yellow-colored cells. Although it is possible 

 that these may be developing planula3, we incline to the opinion that they are 

 parasitic zooxanthellae. We are led to this opinion on account of the decided 

 yellow-green color of these cells, and also because we have found similar cap- 

 sules scattered irregularly over the surface of the sub-umbrella of Laodicea 



