388 MEDUSA OF THE WORLD. 



4 simple lips; unpigmented but iridescent. The 4 radial-canals are bordered with prominent 

 entodermal supporting cells which give them a jagged-edged appearance. South Atlantic, 

 near the Antarctic circle. Only three specimens were found by the Valdivia, but the Belgica 

 found the medusa to be common in the Antarctic Ocean. (See text-figure 237.) 



According to Maas, the bell is higher than a hemisphere when young, but becomes 

 flattened as growth proceeds. Medusae 2 to 3 mm. wide have about 80 tentacles, but when the 

 animal is 6 mm. wide there are 100 to 120 tentacles. 



Homoeonema macrogaster Vanhoffen. 



Homaonema macrogaster, Vanhoffen, 1902, Wissen. Ergeb. deutsch. Tiefsee Expedition, Dampfer Valdivia, Bd. 3, Lfg. I, 

 p. 66, taf. 10, fig. 22. 



Bell 7 mm. wide. 8 radial-canals. 84 tentacles, all of the same size and character. 32 

 lithocysts. Velum well developed. The 8 similar, spherical gonads are adjacent to the sides of 

 the stomach. The diameter across the gonads and stomach is about one-third that of the bell 

 itself. Stomach large, with 4 lips. Bell-margin dark-colored, other parts colorless. A single 

 specimen was found by the Valdivia in the southern part of the Indian Ocean at a depth of 

 100 fathoms, S. lat. 30 7', E. long. 87 50'. (See text-figure 238.) 



Genus TETRORCHIS Bigelow, 1909. 

 Tetrorchis, Bigelow, H. B., 1909, Mem. Mus. Comp. Zool. at Harvard College, vol. 37, p. 123. 



The type species is Tetrorchis erythrogaster Bigelow, from the eastern tropical Pacific. 



GENERIC CHARACTERS. 



Trachymedusae with 8 radial-canals and only 4 gonads, attached to 4 of the radial-canals 

 near their junction with the ring-canal. No peduncle. 4 lips. 



Tetrorchis erythrogaster Bigelow. 

 Tetrorchis erythrogaster, Bigelow, H. B., 1909, Mem. Mus. Comp. Zool. at Harvard College, vol. 37, p. 124, plate 29, figs. 1-3. 



Bell pyriform, 10 to 12 mm. wide, 8 mm. high. Gelatinous substance very thick 

 apically, but thin at margin. 4 perradial tentacles of large size opposite the 4 fertile radial- 

 canals. About 24 swollen tentacles not placed in reference to the radial-canals. Litho- 

 cysts (?) 8 straight, narrow radial-canals, only every alternate canal bearing a gonad. 

 Gonads sausage-shaped and suspended near the bell-margin. Manubrium cylindrical, 

 without a peduncle; as long as the depth of bell-cavity and with 4 small lips. Manubrium 

 brilliant carmine, lips white, other parts colorless. 



Eastern tropical Pacific, 300 fathoms to surface. 6 specimens found by the Albatross 



expedition of 1904-05. 



Genus PANTACHOGON Maas, 1893. 



Pantachogon, Maas, 1893, Ergeb. der Plankton Expedition, Bd. 2, K.c, p. 17; io°4» Result. Camp. Prince de Monaco, fasc. 

 28, p. 29; 1905, Craspedoten Medusen der Siboga Expedition, Monog. 10, p. 55.— Vanhoffen, 1902, Wissen. Ergeb. 

 deutsch. Tiefsee Expedition, Valdivia, Bd. 3, Lfg. 1, p. 62— Monaco (Prince of), 1905, Compt. Rendus Acad. Sci. Paris, 

 tome 140, p. 1 374- 



The type species is Pantachogon haeckelii Maas, from the deep water of the Atlantic. 



GENERIC CHARACTERS. 



Trachymedusae with tentacles arising in a single row from the bell-margin. With gonads 

 not localized, but developed diffusely along the entire lengths of the 8 radial-canals. With 4 

 lips. No peduncle. 



It must be borne in mind that all of the descriptions of the medusae called Pantachogon 

 are based upon the study of preserved specimens. It is possible, therefore, that the "diffusely 

 developed gonads" are only the contracted and opaque edges of the entodermal, supporting 

 lamella along the sides of the radial-canals. 



