380 bulletin: museum of comparative zoology. 



the proportionate length of ribs and meridional canals is individually 

 variable, even in the different canals of a given individual, while 

 different individuals from one haul show the extremes illustrated by 

 palmata and japonica as well as intermediates connecting them. 

 Judging from these facts, no course is open but to refer amboinae, 

 japonica, and the "Albatross" specimens to palmata. That this 

 species should occur both in the Atlantic and in the Indo-Pacific 

 is not at all surprising, indeed, the case exactly parallels that of many 

 oceanic Medusae and Siphonophorae. 



H. fusiformis Agassiz and Mayer, agrees with palmata in its general 

 form, in its tentilla, and in the outlines of its tentacular sheaths, but 

 differs, according to their account, in the fact that the adradial canals 

 join the meridionals above the level of the funnel. Furthermore, 

 their figure (:02, pi. 13, fig. 59) shows the tentacle arising from one 

 end of the base, instead of from the middle, something which, as 

 Moser has pointed out, does not occur in any pleurobrachiid. For- 

 tunately I have been able to study a large series from the Hawaiian 

 Islands, including two specimens labelled by Mayer himself, and 

 though all of them are more or less fragmentary, they are in good 

 enough condition to show that the canal-junction is at the level of 

 the funnel, just as in the eastern Pacific series, and that the structure 

 of the bases of the tentacles is of the usual type. In short, there is 

 nothing to separate them from palmata. Therefore fusiformis can 

 safely be relegated to the synonymy of palmata. It is still a question 

 whether palmata is really distinct from hormiphora, or whether the 

 two are varieties of a single species ; and until the matter is settled, 

 it is better to retain both names. 



One other Ctenophore closely resembles H. palmata, the " Mertensia 

 ovum " of Torrey (: 04, pi. 1, fig. 1), which, as Moser has pointed out, 

 has nothing to do with the genus Mertensia. Its status is somewhat 

 confusing because Torrey does not refer to the figure in his text, nor 

 does he list Mertensia ovum as having been taken at San Diego, where, 

 indeed, its presence would be most unlikely. Judging from the 

 account of his Euplocamis californensis (Torrey, : 04), I have no doubt 

 that the figure in question belongs to that form, and that the legend 

 on the plate is erroneous. So far as the figure shows, the species is 

 probably not separable from H. palmata with which it agrees in general. 

 The only points of difference are that the meridional canals reach 

 almost (but not quite) to the mouth, and that the tentacular sheaths 

 are shorter than is usually the case in palmata. But I have seen one 

 specimen of the latter (Plate 1, fig. 2) almost exactly paralleling 



