INDEX. 



71 



Nebela certesi Penard 

 cratera Wailes 

 dentistoma Pen. . 

 mtr. lacustris Wailes 



PAGE 



. 57 



. 57 



60,61 



, 60 



var. lageniformis Playf . 



60,61 



equicalceus Leidy . 4 



griseola Pen. . .57 



lageniformis Wailes 



58 (syn.), 59 



var. minor Wailes 58, 59 

 martial! Certes . 4, 57 



militaris var. tubulata 



Brown . . 58 



mil way i Wailes . .57 



scotica Brown . . 60 



scutellata Wailes . . 63 



tenella Pen. . . 57 



tropica Wailes . . 63 



tubulata Brown . . 58 



tubulata Pen. . . 58 



vitrsea Cash . . 61 



var. minor Pen. . 62 



var. sphagni Wailes . 61 



NEBELIN.E . . .55 



Pamphagus mutabilis Bailey . 25 



Parmulina Pen. . . 27 



cyathus Pen. . 27. 28 



obtecta (Gruber) Pen. . 28 



PAGE 



Plagiopyxis Pen. . . 44. 46 

 callida Pen. . . 46 



labiata Pen. . . 46 



Pontigulasia compressa 



(Carter) Cash 49, 50 



compressa Rhumbl. 49, 50 



elisa (Penard) SrJiout. . 50 



rhumbleri Hopk. . . 49 



Pseudochlamys patella Clap. 



& Lachm. . . 26 



Pseudodifflugia fascicularis 



Pen. . . .54 



PSEUDONEBELIN.E . . 66 



Pyxidicula Ehrenb. 17, 18, 20, 21 



cymbalum Pen. . 18, 23 



invisitata Averintz. 18, 22 



operculata (Agardh) 



Ehrenb. . 18, 20, 21 



patens Clap. & Lachm. . 18 

 Quadrula symmetrica 



var. irregularis Pen. . 62 

 Quadrulella Cockerell . . 63 



symmetrica (Schulze) 



Cockerell . . 63 



var. irregularis Pen. . 62 

 Trigonopyxis (Diff lugia) 



arcula . . 46 



Trinema enchelys (Ehrenb.) 



Leidy . . 53 



FIG. 176. Pyxidicula operculata. x 800. (After Ehrenberg, 1856.) 



