DIFFLUGIA GLOBULUS. 



37 



reticular venation is not shown in his figure, which cer- 

 tainly represents a sand-covered species which can 

 only be that under consideration. It is probable that 

 in 1856 he figured a different example from the one 

 he described in 1848. Those which appear in his 

 ' Mikrogeologie ' (1854) under the same name are 

 neither sand-covered nor veined, and may not be the 

 same species, most probably being Gentropyxis ecornis, 

 a view apparently held by Leidy. (See ' Freshw. Rhiz. 

 N. Amer.,' p. 305.) It may be noted that Wallich de- 

 scribes one of his figures (f. 17) as of the " typical form, 

 bxit made up of large sandy particles," as if that were 

 the exception rather than the rule. He also figures 

 one (f. 21) "chiefly made up of minute diatoms."] 



52 



53 



54 





Figs. 52-54. — Difflugia globulus: 52, after Ehrenberg, loc. cit. 1856 

 (enlarged) ; 53, from Cocket Moss, W. Torks, drawn by G. S. West 

 (reduced); 54, after Wallich, loc. cit. i. 2a (enlarged). Variously 

 magnified. 



Leidy joins several forms, now recognized as dis- 

 tinct, under the name of " D. globulosa Duj." — connect- 

 ing it with " D. pyriformia Perty " (D. oblonga Ehrenb.) 

 on the one hand, and with D. lobostoma Leidy, on the 

 other. A new genus, PhryganeUa, was established by 

 Penard (' Mem. Soc. Phys." Geneve,' XXXI, 1890) to 

 receive forms diffeinng from D. globidus mainly in the 

 character of their pseudopodia. Empty tests varying 

 in size and structure are met with in Sphagnum, of 

 which it cannot be said positively that they belong to 

 Diffltigi'i, globulus Ehrenb., to Fhri/ganella acropodia 

 (Hertw. & Less.), or to Pseudodiffliigia gracilis Schlumb. 

 One of the forms figured by Leidy under " D. globulosa 

 Duj." is Gentropyxis arcelloides Penard. 



