174 



Papers from the Department of Marine Biology. 

 Linuche unguiculata var. aquila. 



Linerges aquila, HAECKEL, 1880, Syst. der Medusen, p. 496. 



Linuche aquila, MAYER, 1910, Medusae of the World, vol. 3, p. 560, figs. 336 B and c. 



Linuche unguiculata, VANHOFFEN, 1913, Zoologischen Jahrbuchern, Suppl. 11, Heft 3, p. 429. 



This variety 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 is commonly the case in the Atlantic medusa. 8 of the subumbrella 

 sacs in the variety 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 



B 



FIG. 1. A. Showing usual arrangement of subumbrella warts in Linuche unguiculata of the 

 tropical Atlantic. 



B. Showing arrangement of subumbrella warts of the variety aquila of the tropical 

 Pacific. 



C. Enlarged view of central portion of the subumbrella of the variety aquila, showing 

 lips, gonads, and saccules. 



protuberances, an inner zone of 16 large sacs, and an outer of 32 small sub- 

 umbrella 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. 

 In the Atlantic form, the areas of brown cells are commonly developed only 

 centrifugal to the zone of gonads, while in the Pacific variety they occur 

 between the gonads as well as beyond them. A marginal ring-canal is pre- 

 sent. The Pacific variety is, however, found also in the Atlantic. 



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

 Paumotos Islands, and they extend to the coasts of Africa and to Queensland, 

 Australia. They abound in Queensland in the spring months, in Fiji in De- 

 cember, and at Singapore in April. I have studied a large collection of these 



