NO. 1931. NEW MEDUS.T: FROM THE PHILIPPINES— BIGELOW. 255 



Genus ZYGOCANNA Hseckel, 1870. 

 Zygocanna S.^ckeij+ Zygocaniwta KMCKajj+Zygocannula Hjeckel. 



Mayer ^ has summarized our vague knowledge of this, up till now 

 problematical, genus. Its distinguishing feature among ^quorids is 

 the fact that its canals bifurcate. Haackel's accounts, taken from 

 alcoholic material, are incomplete and the condition of his specimens 

 preclude accuracy. Probably his three "species" and the 'pleuronota 

 of Peron and Lesueur are identical. 



The Pliilippine specimens can be described as having branched 

 canals, and it is for tliis reason that I refer them to Zygocanna. But 

 the branching takes place proximal to the margin of the stomach 

 instead of at the margin of the stomach, as Haeckel describes it, and, as 

 inOctocanna, the canals can be traced inward over the roof of the gastric 

 cavity to its center, a feature not previously known for any ^'Equorid. 

 The branching, moreover, is much less regular than Haeckel deemed 

 it, and the subumbrella surface is studded with gelatinous papillae so 

 prominent, even in an alcoholic specimen, that Haeckel could hardly 

 have overlooked them had they been present in his material. 



These facts combined are sufficient grounds for the institution of 

 a new species. The only known medusa with which they may be 

 identical is a young unnamed ^quorid figured and described from the 

 collection of the Siboga by Maas.^ 



ZYGOCANNA VAGANS, new species. 



Mquoride juv. gen.? sp.? Maas, Die Craspedoteu Medusen derjS'i6o5'a- Expedition, 

 1905, p. 44, pi. 4, figs. 22, 23. 



Station 5124, 281-0 fathoms, 1 specimen, 36 mm. in diameter. 



Station 5190, 295-0 fathoms, 1 specimen, 39 mm. in diameter (type), 

 and 9 other fragmentary specimens from 28-30 mm. in diameter. 



Station 5216, 215-0 fathoms, 2 specimens, 76 and 68 mm. in diame- 

 ter; in fair condition. 



The bell is flat; the gelatinous substance thin but stiff, especially 

 in an alcoholic specimen. 



The most interesting feature is the structure of the stomach and 

 of the canals. From the edge of the stomach to the margin of 

 the bell the canals run direct, without branching or anastomosis ; the 

 branching is to be seen within the outer margin of the manubrium. 

 At the center there is a cruciform figure, exactly as in Irenopsis and 

 Octocanna, which can be reduced to four primary arms, though often 

 irregular, and especially so in the type. Passing outAvard from the 

 center the canals (or rather the lines on the roof of the manubrium, 

 which represent their location at early stages) branch dichotomously, 

 each main trunk, with its descendent branches, bifurcating three or 



> MedusfT of the World, vol. 2, 1910. 



i Die Craspedotcn Medusen dcr Si&ojya-Expedition, 1905. 



