Prof. Bailey on Fossil and Recent Infusoria. 325 



These truly elegant forms have the habit of Actinoptychus, 

 but in addition they have near the margin a row of lateral spines, 

 (somewhat like the processes of Eupodiscus, but far more nume- 

 rous,) which probably connect the animalcules together in the 

 young state. By a happy idea, Ehrenberg has dedicated the dif- 

 ferent species of this genus (which must always be a favorite 

 among lovers of the microscope) to persons distinguished in the 

 history of microscopic research. The species with six radiant 

 septSB and three elevated radiant portions, is named Heliopelta 

 Metii, after Jacob Metius, to whom Ehrenberg ascribes the dis- 

 covery of the microscope in 1606. The species with eight septas 

 and four elevated portions, represented in fig. A, is called H. 

 Leeiitoenhoekii, in honor of Leeuwenhoek, who discovered ani- 

 malcules in 1675. To Euler, for his researches upon achroma- 

 tism in 1757, is given the species H. Euleri, with ten septse and 

 five elevations. To SeUigue, for improvements in the structure 

 of the microscope in 1823, is given the species H. Selligueii, 

 with twelve septae and six elevations. And Ehrenberg suggests 

 that new species may hereafter be dedicated to Dollond for his 

 achromatic inventions, and to Otto Miiller for his microscopic re- 

 searches. It is to be hoped that some species worthy of bearing 

 the name of the greatest microscopic observer of the present age 

 may be added to this list, as H. Ehrenhergii. 



The different species of Heliopelta are very abundant in the 

 Bermuda Tripoli, and have not yet been noticed at any other 

 locality. 



3. " Omphalopelta, nov. gen. — Animal e Bacillariis Naviculaceis lib- 

 erum. Lorica simplex Bequaliter bivalvis silicea orbicularis (non con- 

 catenata.?) intus sepimentis imperfectis in loculos radiantes extus alterne 

 impresses divisa, centre laevi, aperturis obsoletis, spinulis in utriusque 

 lateris summo margins raris erectis oppositis." 



This genus has the habit of Actinoptychus and. Heliopelta, but 

 differs from the former in the presence of lateral spines, and from 

 the latter by the small number of these processes. The species 

 of these three genera often closely agree in their form as well as 

 in the number of their radii and cells, but the character of the 

 spines will always distinguish them. 



4. "Systefhania, nov. gen. — AniiTial e Bacillariis Naviculaceis libe- 

 rum. Lorica simplex sequaliter bivalvis silicea orbicularis (concate- 

 nata?) Valvularum testa cellulosa nee radiata nee septata, corona 



Vol. xLviii, No. 2.— Jan .-March, 1845. 42 



