560 MEDUSA OF THE WORLD. 



Linuche aquila. 

 Plate 59, fig. n. 



Liner ges aquila, HAECKEL, 1880, Syst. der Medusen, p. 496. GOETTE, 1886, Sitzungsber., Akad. Wissen., Berlin, Jahrg., p. 833. 

 AGASSIZ, and MAYER, 1899, Bull. Museum Comp. Zool. at Harvard College, vol. 32, p. 170, plate 10, figs. 33, 34; 1902, 

 Mem. Ibid., vol. 26, p. 156. 



(?) Linerges draco, HAECKEL, loc. cit., p. 496. 



Linerges draco (young medusa), MAAS, 1903, Scyphomedusen der Siboga Expedition, Monog. 1 1, p. 24, taf. I, fign. I, 2. 



This form is widely distributed over the tropical Pacific and is closely related to the 

 tropical Atlantic L. unguiculata, with which it is identical in form and dimensions, being 

 about 13 mm. high and 16 mm. wide. It has 48 wart-like protuberances upon the subumbrella 

 arranged in 2 rows instead of in 3 as in the Atlantic medusa. 8 of the subumbrella sacs in 

 L. aquila alternate with the gonads and 8 arise from the sides of the gonads themselves. 

 Thus in the Pacific medusa we have two zones of protuberances, an inner zone of 16 large 

 sacs, and an outer of 32 small subumbrella saccules. The 16 large sacs lie in the mid-regions 

 of the gonads, while the 32 small saccules lie at the zone of the outer ends of the gonads. 

 The areas of brown cells are developed only centrifugal to the zone of gonads in the Atlantic, 

 while they occur between the gonads as well as beyond them in the Pacific medusa. A marginal 

 ring-canal is present. 



FIG. 356. A, arrangement of subumbrella warts in Linuche unguiculata of the 

 tropical Atlantic. B, arrangement of subumbrella warts of Linuche aquila 

 of the tropical Pacific. C, enlarged view of central part of subumbrella of 

 Linuche aquila, showing lips, gonads, and saccules. 



Vast swarms of these medusae are found among the atolls of the Fiji and Paumotos 

 Islands, and they extend westward to the coast of Africa. They abound in the spring months, 

 in Fiji in December and at Singapore in April. I have studied a large collection of these 

 medusae taken in the Philippine Islands at Mactau, near Sibu, on April 6, 1908, by the U. S. 

 Bureau of Fisheries steamer Albatross. All were mature. 



There appear to be no valid distinctions in Haeckel's descriptions between L. aqutla 

 and his " L. draco" the differences being such as one would expect to find in two contracted 

 preserved specimens. Haeckel's Linantha lunulata (Syst. der Medusen, p. 494, taf. 29, fign. 

 i to 3) is possibly the young of L. aquila. It is said to have 4 interradial horse-shoe-shaped 

 gonads, but in all known species of Linuche the gonads are more nearly perradial than inter- 

 radial. It is evidently an immature form, being only 10 mm. wide, and has no subumbrella 

 saccules; indeed, the figure itself shows its ephyra-like condition. It comes from the Gala- 

 pagos Islands, off the Pacific coast of South America. 



