NORTH AMERICAN EARLY TERTIARY BRYOZOA. 267 



FIG. 73. Family Thalamoporellidae Levinsen, 1909. 



A. Thalamoporella novae hollandiae Ha swell, 18S1. Three zooecia with their operculum 

 and an onychocellariuin, X 40. (After Levinsen, 1909.) 



B-D. Thalamoporella rozieri Audouin. 1826. B, C. Onychocellarium, X 50, and mandible, 

 < 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 granulala vnr. tubifera Leviusen, 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 zooedum after the removal of the 

 basal surface ; the independent basal wall of the polypide tube is seen, X 40. 



K. Thalamoporella mamillaris Lainouroux, 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.) 



