382 P- Kramp. 



part of the hydrothecal wall; the whole of the distinctly 

 marked roof is thrown off. 



In Cali]cella the operculum is formed of the peripheral 

 part of the hydrothecal roof; its central part is thrown off. 



The opercula in Ciispidella and Calijcella are thus not homologues 

 and it is therefore quite unjustifiable to place them together under 

 one genus. 



Nor do I think it right to unite Ciispidella and Campamilina. 

 The opercula in the two genera are certainly in the main of the 

 same construction, only somewhat more regular in Campamilina, but 

 there are two things which separate the two into naturally contrasted 

 groups: 1) the form of the hydrotheca, 2) the form of the gono- 

 theca. In Campamilina the hydrotheca is a calycle on a twisted 

 pedicel, whereas in Ciispidella it is tube-shaped and quite without 

 pedicel. The gonotheca is certainly only known for one species of 

 Ciispidella, it is formed quite like a hydrotheca, but is longer; it is 

 just this resemblance which was the cause of this gonotheca not 

 being found until a few years ago, and the same fact makes it to a 

 high degree probable, that the gonothecae in the other species of 

 Ciispidella have a similar form and have thus been overlooked 

 hitherto. 



In Campamilina, as is known, the gonotheca has quite a different 

 form. I think, therefore, that there is every reason, to keep Ciispi- 

 della as an independent genus. 



On the other hand, I agree with Broch in placing Opercularella 

 under Campamilina; its trophosome is of the same structure, but 

 Opercularella has sessile gonophores, whilst Campamilina produces 

 free medusae. 



Lafoëina. — The hydrotheca is formed quite as in Ciispidella, 

 but the possession of nematophores shows, as Вноси rightly remarks, 

 that Lafoëina must occupy a higher position within this family. 



Tetrapoma and Lovenella. — As above hinted, the operculum in 

 these genera, according to Broch, is also formed of the upper part 

 of the hydrothecal wall; the free valves of the operculum would then 

 correspond to the triangular facets, and the thinner parts should 

 not only split but be completely thrown off, so that the facets 

 become free: "Die Entwickelung des Opercularapparates ist bei der 

 Lovenella [to which Broch ascribes Tetrapoma Lev.] etwas weiter 

 geschritten. Hier haben sich die dickeren Teile des Campaniilina- 

 Deckels voneinander gänzlich getrennt und sind and den Hydrotheken 



scharf abgesetzt ". Quite apart from what is unreasonable in 



this view, I am able to i)roduce positive evidence that the operculum 

 in Tetrapoma is formed from the original roof of the hydrotheca; 



