ENDVCTIA. 



445 



GENUS 110. ENDYCTIA EHR., 1845. 



Frustules cellular, simple, or forming a short filament. Valves 

 circular, reticulate, or areolate, with raised denticulate margins. 



The genus Endyctia is related on one side to Stephanopy.xis and Melosira, 

 and on the other to Coscinodiscus. We represent in the text (fig. 169) Endyctia 



Fig. 169. Endyctia oceanica. 



oceanica Ehr., found in Peruvian guano, and found also by Dr. Pantocsek in 

 a fossil state in Hungary. The genus includes about a dozen species, all of 

 which (with the exception of Endyctia Campeclriana Grun.) have been found 

 in Hungary. 



GENUS 111. CYCLOTELLA KUTZ. 1833. 



Valve disc divided into two portions, the 

 exterior annular, with striae smooth (costae) or 

 punctate, more or less fine, sometimes inter- 

 mixed with small spines ; always without a 

 pseudo-nodule ; centre often bullate, smooth or 

 granular, with granules sparse or radiating. 

 Girdle face straight or undulate. Frustules not 

 united in a band. ' 



Some fifty Cyrfotdla have been described or named. These diatoms are 

 spread over the whole world, and are found in a fossil state as well as living ; 

 a considerable number of species are small and the greater number have 

 undulated valves ; they are especially differentiated from Melosira by never 

 being joined by long bands, but, at most, are only found united by two or 

 three individuals. The species figured in the text is Cyclotella Kiitzingiana 

 var. Schumanni 'Grun. (fig. 170.) 



Fig. 170. 



Cyclotella Kiitzingiana 

 var. Schumanni. 



