NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
141 
The following species, are classed in this genus: 
Alder ina ( Membranipora ) imbellis Hindis, 1860. Recent. 
Alderina ( Membranipora ) irregularis Smitt, 1872. Recent. 
Alderina (Membranipora) solidula Hindis, 1860. Recent. 
Alderina (Bifhtstra) ovalis D’Orbignv, 1852. Senonian. 
Alderina (. Flustrellaria ) franqana D’Orbigny, 1852. Senonian. 
E. Eegella F. Stamenocella G. Megapora Ammatophora I . Marssonopora 
Fig. 35. — Genera of Membraniporae with ovicells never closed by the opercular valve. 
A. Alderina imbellis Hincks, 1880, X 25. Recent. 
B. Callopora lineata Linnaeus, 1758, X 50. Recent. 
C. Amphiblestrum flemingi Busk, 1875, X 50. Recent. 
D. Ramphonotus minax Busk, 1860, X 25. Recent. 
E. Tegella unicornis Fleming, 1828, X 20. Recent. 
F. Stamenocella pyriformis, new species, X 20. Lower Jacksonian, Jackson, Mississippi. 
G. Megapora ringens Hincks, 1880, X 50. Recent. 
H. Ammatophora nodulosa Hincks, 1880. Recent. 
I. Marssonopora dispersa Hagenow, 1837. Cretaceous (Senonian) Isle of Riigen. 
Alderina ( Membranipora ) abortiva Canu, 1911. Rocanean. 
Alderina ( Membranipora ) cummingsi Canu, 1911. Rocanean. 
Alderina ( Membranipora ) pcrisporsa Novak, 1877. Cenomanian. 
The recent species Alderina irregularis Smitt, 1872, is very important in the 
American forms, and as it has been confused with other species we believed it useful 
to make known its synonymy and history. 
