126 THE MEDUSAE. 



Browne has already pointed out (: 04, p. 740) that Pentachogon apsteini 

 Vanhoffen, foi- which he has instituted this genus, is to be separated from 

 Aghscera, its closest ally, by the form of the gonads and of the bell, as 

 well as by the much more remarkable fact that the Maldive specimens 

 of P. apsteini were hermaphroditic. Inasmuch as hermaphroditism has never 

 been observed, so far as I can learn, in any other Trachomedusa, I 

 was of course particularly glad of the opportunity to test its occurrence 

 in a second series of A. apsteini from a different locality. The result of 

 this study, prosecuted on cross sections of the gonads, has been to show that 

 these Pacific specimens are 7iot hermaphroditic, but follow the more usual 

 plan, all the gonads of any given individual being either male or female. 

 The explanation of this remarkable dimorphism in different lots of this one 

 species must be sought on more extensive material from various regions. 



Amphogona apsteini Vanhoffen. 



Pentachogon apsteini Vanhoffen, : 02'', p. 65, taf. 10, fig. 18, taf. 11, fig. SS. 

 Amphogona apsteini Browne, : 04, p. 740, pi. 54, fig. 5, pi. 55, fig. 5, pi. 56, fig. 1, 

 pi. 57, figs. 10-13. 



Plate 2, Figs. 1, 2 ; Plate 34, Figs. 12-15 ; Plate 45, Fig. 10. 



Acapulco Harbor, February 28 ; surface ; 6 specimens, from 2.5 mm. to 

 6 ram. in diameter. 



Browne has given us such a good account of this species that I have but 

 little to add to his description, with which the present specimens closely 

 agree except for the gonads, as noted above. 



The diameter of the largest specimen, 6 mm., is somewhat greater than is 

 recorded by Browne (4.25 mm.). In outline the living specimens were less 

 flattened, being about twice as broad as high (PI. 2, fig. l), and slightly 

 conical. Tiie gelatinous substance is thin, but rigid. In the large speci- 

 mens the peduncle hangs about to the bell opening, and is rather narrow 

 (PI. 34, fig. 15). 



Tentacles. — In the largest specimen, 6 mm. in diameter, there are about 

 sixty-four tentacles, usually eight per octant, though the number varies 

 somewhat. Browne has recorded seventy tentacles for a rather smaller speci- 

 men, so it is evident that as in most Trachynemidae the number is individ- 

 ually variable. In the smallest specimen, 2.5 mm. in diameter, there are 

 only about forty. All the tentacles are of one type, though, from their 



