NORTH A-MERU'AX EARLY TERTIARY BRYOZOA. 



139 



KEY TO AMERH.AX SPECIES OF MEMBEANIPORIDEA. 



, |Zoarium bilauiellar ' 2 



[Zoariuui incrustiug : 3 



2. 



|Gyumocyst convex without lateral grooves HI. porrecta. 



[Gymnocyst concave with lateral grooves. _ HI. spissimuralis. 



3 | Ovicell with porous floor .-I/, oecioporosa. 



JFloor nouporous 4 



4 fOvicell very small M. pyriformis. 



[Ovicell large, transverse 5 



,. |Gymuocyst present 31. laticella. 



[No gymnocyst 6 



JTwo primoserial nondefornied zooecia (Iz 0.55 mm.) M. trigemma. 



[One primoserial deformed zooecium (/~ 0.40 nun.) M. similis. 



6. 



F-is 



FIG. 33. Genus Tremopora Ortniann, 1890. 



A-E. Trniioporn rudicifcra Hincks. 1881. A. Several zooecia with ovicell, X 23. B. 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 Hincks, 1SS1.) 



F. Tremoiiora dendracantha Ortmann. 1890. Several zooecia showing the large bifurcated 

 oral spines, X 15. (After Ortmann. 1890.) 



Genus TREMOPORA Ortmann, 1890. 



1890. Tremopora OKTMANX. Die Japonische Bryozoen Fauna, Archiv. fur Naturgeschichte, 

 vol. 50, p. 29. 



The opercular A'alve always closes the ovicell. The mural rim bears one or two 

 large bifurcated oral spines and an avicularium moi - e 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 Mi inln-nnipora patellaria group. Levinsen incorporated it in his family 

 Bicellariidae. 



