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NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
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Fig. 73. — Family Thalamoporellidae Levinsen, 1909. 
A. Thalamoporella novae hollandiae Haswell, 1881. Three zooecia with their operculum 
and an onychocellarium, X 40. (After Levinsen, 1909.) 
B-D. Thalamoporella rozieri Audouin, 1826. B, C. Onychocellarium, X 50, and mandible, 
X 85. D. Section of ovicell, X 85, showing two larvae, of which the right one is clearly older 
than the left. (B-D after Waters, 1908.) 
E. Thalamoporella granulata var. tubifera Levinsen, 1909. Two gonozooecia, X 40. (After 
Levinsen, 1909.) 
F-J. Thalamoporella lioticha Ortman, 1890. F. Median section of ovicell, X 40. G. Sche- 
matic longitudinal section through ovicell, X 40. H. Ovicell with frontal half cut away, showing 
the operculum, X 40. I. Opercula. J. The distal end of a zooecium after the removal of the 
basal surface ; the independent basal wall of the polypide tube is seen, X 40. 
K. Thalamoporella mamillaris Lamouroux, 1816. Five opesiules of different zooecia, show- 
ing the variation in shape of the opesiular outgrowths and in the number and structure of the 
protecting spinous processes; X 75. 
L. Spicula of Thalamoporella novae hollandiae Haswell, 1881, X 200. 
M. Basal surface of the Thalamoporella granulata Levinsen, 1909, X 23, where may be seen 
the polypidian tube and the opesiular chambers. (F-M after Levinsen, 1909.) 
