HYDEOMEDUSAE, SIPHONOPHORES, AND CTENOPHORES. 315 



aequorids is the fact that its canals bifurcate. Haeckel 's p accounts, 

 taken from alcoholic material, are incomplete, and the condition of 

 his specimens precluded accuracy. Probably his three " species " 

 and the pleuronota of Peron and Lesueur are identical. 



The Philippine specimens can be described as having branched 

 canals, and it is for this reason that I refer them to Zygocanna, but 

 the branching takes place at the margin of the stomach instead of 

 distal to it, as Haeckel describes it; and the canals can be traced 

 inward over the roof of the gastric cavity to its center, a feature not 

 previously described for any aequorid. The branching, moreover, is 

 much less regular than Haeckel deemed it, and the subumbrella sur- 

 face is studded with gelatinous papillae so prominent, even in alco- 

 holic specimens, that Haeckel could hardly have overlooked them 

 had they been present in his material. Furthermore, there is no 

 peduncle, which separates them from his Zygocannula diploconus, 

 and there are many more tentacles than in his pleuronota. It is not 

 worth while discussing the Aequorea purpurea of Peron and Lesueur 

 (1809), which is also placed by Haeckel in "Zygocannota" because 

 the structure of the gonads is so remarkable as to need confirmation. 

 These facts combined are sufficient grounds for the institution of a 

 new species. The only known Medusa with which it may be identical 

 is a young unnamed aequorid figured and described from the collec- 

 tion of the Siboga by Maas (1905). 



ZYGOCANNA VAGANS Bigelow. 



Plate 42, figs. 5-7 ; plate 43, fig. 6. 



Zygocanna ragans Bigelow, 1912, p. 255. 



aeguoride juv. gen? sp? Maas, 1905, p. 44, pi, 4, figs. 22, 23. 



Zygocanna vagans — material examined. 



There is little to add to my original description (1912), except the 

 accompanying illustrations, the most important being those showing 

 the structure of the stomach and the method of branching of the 

 canals. The important fact is that the branching takes place at the 

 margin of the stomach. And the cruciform figure formed by inward 



