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NORTH AMERICAN LATER TERTIARY AND QUATERNARY BRYOZOA. 153 
Those of the smaller set occur in the depressed spaces, usually close beside the zooecial orifice, and 
rarely on the reverse of the branches. 
This common species of the Choptank formation apparently belongs to the Retepora-cellulosa group 
of Waters. Though resembling several of the species of the group rather closely we could not decide 
that it was any nearer to one than to another. Still, having found it difficult to make thoroughly 
satisfactory comparisons, we will not be greatly surprised should future study prove R. dovcrensis to 
belong to some previously described species. 
The peristome bears a wide, very irregular, rimule spiramen. The ovicell is 
fissured. 
Occurrence .—Miocene (Choptank formation): Dover Bridge and Jones Wharf, 
Maryland (common). 
Cotypes and plesiotypes. —Cat. Nos. 68660, 68661, U.S.N.M. 
E. Schizellozoon F. Triphyllozoon G. Schizotheca H.Lepraliella 
Fig. 27.— Genera of the family Reteporidae Smitt, 1867. 
A. Relepora bcaniana King, 1846, X 25. Recent. (After Hincks, 1880.) B. Phidolopora labiata 
Gabb and Horn, 1865, X 20. Pleistocene of California. C. Rhynchozoon angulatum Levinsen, 
1909, X 55. Recent. (After Levinsen, 1909.) D. Hippellozoon novaezelandiae Waters, 1894, X 25, 
Recent. (After Waters, 1894.) E. Schizellozoon imperati Busk, 1884, X 25. Recent. (After Waters, 
1885.) F. Triphyllozoon moniliferum MacGillivray, 1860, X 85. Recent. (After Waters, 1894.) 
G. Schizotheca fissa Busk, 1858, X 45. Recent. (After Hincks, 1880.) H. Lepraliella contigua Smitt, 
1867. Recent. (After Levinsen, 1916.) 
12 184—23—Bull. 125-11 
