MEDUSAE. I. 



founded by Haeckel owing to a false supposition (the presence of clubs), and because the descrip- 

 tion, therefore, is erroneous. On the other hand, the characterisation of the genus Melicertum, given 

 by Agassiz on the basis of the species campanula, is clear and correct. Moreover the genus Melicertum 

 Agassiz is older than Melicertidium Haeckel. Before we decide to release the name Meh'certum we 

 must, therefore, examine how far the use of that name may give rise to a continued confusion. 



First we must examine the fate of the different species of "Melicerta" and "Melicertum^. In 

 order to illustrate the question I have worked out the adjacent synopsis (Table V) including (first 

 column) all species of the genera Melicerta Peron & Lesueur and Melicerttim sensu Oken and Esch- 

 scholtz. In the second column I have recorded by whom and when these generic names have been 



Table V. Synopsis of the Species of Melicerta Peron & Lesueur and Melicertum 



Oken and Eschscholtz. 



Generic name Melicerta or Melicertum used 



First time 



Last time 



Name now used 



Pron & Lesueur 1809: 



Melicerta digitale (O. F. Mull.) 



campanula (Fabr.) 



perla (Slabber) 

 pleurostoma nov. 

 fasciculata nov. 



Eschscholtz 1829: 



Melicertum campanulatum (Chamisso) 1 

 penicillatum nov. 

 pusillum (Swartz) 2 



Lesson 1 843 : 



Melicerta morchella nov. 



Melicerta digitale Per. & Les. 1809 

 Melicertum campanula Fewkes 1888 

 Melicerta perla Blainville 1834 



pleurotoma Lesson 1843 

 fasciculata Lesson 1843 



Melicertum campanulatum Dujardin 1840 

 penicillatum Lesson 1843 

 pusillum Lesson 1843 



;not mentioned later) 



1 Used by Ehrenberg 1836 and Thompson 184} for M. octocoslalum Sars. 

 1 Used by L. Agassiz 1862 and Kb Hiker 1864 for Af. oclocoslaium Sars. 



Aglantha digitalis 

 ? Catablema campanula 

 Pelagia perla 

 Turritopsis pleurostoma 

 Rathkea fasciculata 



Polyorchis campanulatus 



penicillata 

 ? swimming actinia-larva 



(undetermined) 



used for the last time for the species in question. Finally, the last column gives the names, which are 

 now commonly used for these species. Meticertum pusillum Eschscholtz and Melicerta morchella Les- 

 son have not later been identified. 



The application of the name of Melicertum campanulatum in Ehrenberg (1836) and of 

 Melicertum pusillum in L. Agassiz (1862) is simply due to erroneous identifications, which are, in- 

 deed, regrettable enough, but they have done no continuous harm and are of no importance whatever 

 with regard to the question here discussed. 



When campanula is temporarily excepted, we will see, from the synopsis, that the use of the 

 names Melicerta and Melicertum in the old meaning (sensu Peron & Lesueur, Oken, and Eschscholtz) 

 ceases entirely after the year 1843 (Lesson), in the case of some species even earlier, thus, in any 

 case, long before L. Agassiz used Melicertiim in a new meaning. 



When Melicertum campanula sensu Agassiz still as late as in 1888 (Fewkes 1888 b) is recorded 



