NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
139 
KEY TO AMERICAN SPECIES OF MEMBRANIPOEIDRA. 
1 [Zoarium bilamellar. 
| Zoarium iucrustiug. 
2 [Gymnocyst convex without lateral grooves : 
[Gymnocyst concave with lateral grooves 
2 [Ovicell with porous floor 
[Floor nonporous 
4 [Ovicell very small 
[Ovicell large, transverse 
g | Gymnocyst present 
[No gymnocyst 
^ [Two primoserial nondeformed zooecia (Is 0.55 mm.) 
1 0ne primoserial deformed zooecium ( Is 0.40 mm. ) 
2 
__3 
porrecta. 
_.M. spissimuralis. 
._M. oecioporosa. 
__4 
__M. pyriformis. 
_.5 
,M. laticella. 
,_6 
—M. trigemma. 
— M. similis. 
Fig. 33. — Genus Tremopora Ortmann, 1890. 
A-E. Tremopora radicifera Hindis, 1881. A. Several zooecia with ovicell, X 23. 15. Avicu- 
larian mandible, X 55. C. View of the basal surface, X 23. (A-C after Levinsen, 1909.) 
D. View showing radicular pores and pore tubes. E. Radical fibers. (D, E after Hindis, 1881.) 
F. Tremopora dendracantha Ortmann, 1890. Several zooecia showing the large bifurcated 
oral spines, X 15. (After Ortmann, 1890.) 
Genus TREMOPORA Ortmann, 1890. 
1890. Tremopora Ortmann, Die Japonisclie Bryozoen Fauna, Archiv. fur Naturgeschichte, 
vol. 50, p. 29. 
The opercular valve, always closes the ovicell. The mural rim bears one or two 
large bifurcated oral spines and an avicularium more or less developed. 
Genotype.- — Tremopora dendracantha Ortmann, 1890. 
Range. — Helvetian-Recent. 
The zooecia are adjacent or. separated and are joined among themselves by 
connecting tubes. The lower face often has radicels. Waters classed this genus 
in the Merribranipora patellaria group. Levinsen incorporated it in his family 
Bicellariidae. 
