MEDUSAE. 147 



Rhegmatodes lacteus, sp. nov. 



Plate o, fiys. 15, 16. 

 The bell is flatter than a hemisphere, and is 50 mm. in diameter. The 

 gelatinous substance is thick at the apex, but thin at the bell-margin. A 

 long funnel-shaped depression, at the apex of the bell, extends downward 

 almost to the level of the stomach. There are ten well developed tentacles, 

 each of which is about one-tenth as long as the bell-diameter. These ten- 

 tacles are provided with large hollow, bulbular bases. In addition to these 

 large tentacles there are about 250 very small rudimentary ones. There 

 are about 500 otocysts, each containing two small spherical otoliths. The 

 velum is delicate and narrow. There are 105 straight, narrow radial canals, 

 upon the middle and lower regions of which the gonads are developed. The 

 stomach is 25 mm. in diameter, and the canals arise from its periphery. The 

 proboscis is short, and there are 105 simple lips. The tentacles, proboscis, 

 and genital organs are of a translucent milky color. A single specimen 

 was found in a surface haul a few miles north of Tahiti. 



Station 73; October 5, 1899: S. Lat. 17° 27', W. Long. 149° 32'. 



Mesonema macrodactylum Brandt. 



Mesonema macrodactylum Brandt, J. F., 1838; Mem. Acad. Imp. St. Petersbourg, Sci. Nat. 

 Ser. G, Tom. IV., p. 359, Taf. IV. 



Large numbers of this medusa were found swimming at the surface in 

 the lagoon of Likieb Atoll, Marshall Islands, on January 20-21, 1900. The 

 tentacles are not quite so long as in Brandt's figures. The entoderm of the 

 canals, tentacle bulbs, and lips is slightly milky in color ; all other parts of 

 the medusa being colorless. Brandt describes this species from the tropical 

 Pacific, and Chun (1896 ; Mitt. Nat. Mus. Hamburg, Jahrg. 13, p. 7) records 

 it from the coast of Zanzibar. 



Polycanna purpurostoma Agassiz and Mayer. 



Polycanna purpurostoma Agassiz and Mayer, 1899 ; Bull. Mus. Comp. Zobl., Vol. XXXII., 

 p. 1G9, PI. 8, Figs. 26-28. 



A single specimen of this medusa, 50 mm. in diameter, was obtained in 

 a surface tow made off Tahaa Island, Society Islands, on November 16, 1899. 

 We found it among the Fiji Islands in December, 1897. 



