MAYER: MEDUS/E FROM THE WESTERN ATLANTIC. 5 



SYNDICTYON, A. Agassiz, 1862. 

 Syndictyon angulatum, nov. sp. 



Figs. 6-8, Plate 3. 



Specific Characters. — The bell is almost square in cross-section and is not 

 quite as broad as it is bigh. The bell height in the specimens found by us 

 was about 2.5 mm. There are 4 stiff tentacles that are about three-fourths 

 as long as the bell height. The distal halves of these tentacles are conical in 

 shape, and are covered thickly with clusters of nettle cells. The basal bulbs 

 of the tentacles are large and swollen, and contain each a single well-developed 

 ectodermal ocellus. This ocellus is formed by a cup-shaped invagination of 

 ectodermal cells that are deeply stained with dark-brown pigment granules. 

 It is probable that this structure constitutes a very primitive udoscopic eye. 

 The velum is small. There are 4 narrow, straight, radial tubes and a slender 

 circular vessel. The proboscis is spindle-shaped, and the mouth is a simple 

 circular orifice. The gonads are situated within the ectoderm of the proboscis. 

 The entoderm of the proboscis and of the tentacle bulbs varies from turquoise 

 to blue-green in different specimens. 



Several specimens of this medusa were found off Turks Islands, Bahamas, 

 January 20, 1893. 



BOUGAINVILLIA, Lesson, 1836. 

 BougainviHia Gibbsi,^ nov. sp. 



Figs. 14, 15, Plate 4. 



Specific Characters. — Adult medusa ; Figure 14. The bell is about 4 mm. 

 in height and 3.8 mm. in diameter. The gelatinous substance is very thick, so 

 that the bell cavity is only about one half as deep as the height of the animal. 

 There are 4 clusters of marginal tentacles which arise from 4 large bulbous 

 swellings, situated at the bases of the 4 radial canals. Each bulbous swelling 

 gives rise to 4 or 5 long slender tentacles. There is a single dark-brown 

 ocellus at the base of each tentacle upon the centripetal (loVer) side. The 

 velum is small. There are 4 straight, narrow, radial canals. The proboscis 

 is wide and cruciform in cross-section, and the radial canals arise from the 

 4 corners of the cross. The proboscis is short and does not extend quite one 

 half the distance from the inner apex of the bell cavity to the velar opening. 

 The mouth is situated at the extremity of a short tubular neck, and there are 

 no prominent lips. Four radially situated oral tentacles arise from the sides 

 of the neck of the proboscis. Each one of these branches dichotomously 

 about twice. The gonads are developed upon the sides of the stomach, and 



i Named for Mrs. Theodore K. Gibbs. 



