740 EDWARD T. BROWNE. 



Amphogona apsteini (Vanhoffen), 1902. (PI. LIV. fig. 5, PI. LV. fig. 5, PI. LVI. fig. 1, 



PI. LVII. figs. 10—15.) 



Pantachogon apsteini, Vanhoffen (1902, p. 65, Taf. x. fig. 18, Taf. xi. fig. 28). 



The genus Pantachogon was instituted by Maas (1893) for a species {P. Iiaeckelii) found 

 in the North Atlantic. This medusa has a series of spindle-shaped gonads along nearly the 

 whole length of the radial canals. The stomach is not situated upon a peduncle, and the 

 genus belongs to the Trachynemidae. Vanhoffen has slightly altered Maas' original definition 

 of the genus for the inclusion of his new species, P. apsteini, found on the west coast of 

 Sumatra. This species has oval gonads near the margin of the umbrella, and the stomach 

 is situated upon a distinct peduncle. It has the characters of the Aglauridae. 



The specimens in this collection agree very closely with the description and figures of 

 Pantachogon apsteini, and I believe that they belong to that species. According to the 

 classification adopted by Haeckel, and by Maas, the Maldive specimens would belong to the 

 genus Agliscra, as the eight gonads are upon the sub-umbrella. But in one respect, however, 

 there is a considerable difference. The shape of the umbrella is unlike that of the Aglauridae, 

 and is more like that of the Trachynemidae. In Agliscra the umbrella is about twice as 

 high as broad, whereas in the Maldive specimens the umbrella is about two to three times 

 as broad as high. If one imagined an Agliscra with its umbrella flattened out then it 

 would resemble this species. I do not think that the Maldive specimens or Vanhoffen's 

 specimens belong to the genus Pantachogon of Maas, as they are not like the type sj)ecies, 

 P. haeckelii. They show a nearer relationship to Agliscra. I think it is best to institute 

 a new genus, to which I give the name Amphogona {a fKJxo-yov)]) and place it in the 

 family Aglauridae. 



Specific Characters. Umbrella saucer-shaped, with thin walls, about twice to three 

 times as broad as high. Velum fairly broad. Stomach small, situated on a short peduncle. 

 Mouth with four thick lips. Eight radial canals. Eight globular or oval gonads, situated 

 upon the radial canals near the margin of the umbrella ; bisexual, male and female gonads 

 upon alternating canals. About 70 or more tentacles, uniform in shape. Sense organs 

 external, ?16. 



Size. Umbrella 4-^ mm. in width and 1| mm. in length (the largest specimen). 



Distribution. Indian Ocean; West coast of Sumatra (Vanhoffen); Maldive Islands, Mila- 

 dumadulu (Gardiner). 



The collection contains three specimens. 



A. An intermediate stage. Umbrella 2^ mm. in width and li mm. in height. Stomach 

 a little longer than the peduncle, which measured 025 mm. Gonads just beginning to develop 

 and varying slightly in size. About six tentacles and one sense organ in each octant. 



B. An immature adult. Umbrella 4 mm. in width and 1^ mm. in height. Stomach 

 on a peduncle, which measured 0"6 mm. in length. Eight globular gonads, male and female 

 on alternating canals, all about the same size and shape. Tentacles, 57. Sense organs, 10 

 (six octants with one sense organ and two octants with two sense organs). 



C. An adult. Umbrella 4| mm. in width and If mm. in height. Stomach on a peduncle, 

 which measured about 05 mm. in length, and twice as long as the stomach. Eight oval 

 gonads, male and female on alternating canals. Tentacles, 74 (the following numbers in each 



