NORTH AMERICAN EAKLY TERTIARY BRYOZOA. 677 



FIG. 219. Family Heteroporidae Pergens and Meunier, 1S86. 



A-D. Heteropora claviformis Waters, 1904. A. Zoarium, natural size. B. Portion of a sur- 

 face, X 25. C. A broken colony, X 3, showing the transverse section. D. Longitudinal decalci- 

 fied section, X 85, showing closures traversed by the mesenchyme and the vesicular wall. His- 

 tolysis had commenced. (After Waters, 1904.) 



E-F. Heteropora neozelanica Busk, 1S79. E. Zoarium, natural size. F. Portion of the sur- 

 face, enlarged. (After Busk, 1S79.) 



G-P. Heteropora pelliculata Waters, 1870. G. Zoarium, natural size. H. Longitudinal sec- 

 tion, X 25, drawn with the growing end downward. I. Surface, X 25, with portion to right 

 showing thin covering removed. 3. Transverse section, X 25. K. Portion of the transverse sec- 

 tion, X 50. (G-K after Waters, 1879.) L. Section showing the interzooecial pores and the hair- 

 like spines, X 50. M. Interzooecial pores, X 150. (L, M after Waters, 1884.) N. Portion of 

 the surface of a colony, X 40, showing the projection of the zooecial tubes beyond the surface 

 (zoe) when in a sheltered position. O. Portion of the surface of a branch X 40, showing the 

 zooecial apertures (soe. op.) and the apertures of the interstitial canals (ruesopores) (inter. 

 can.). P. Portion of the surface of a colony, X 40, in which the interstitial canals are covered 

 by a delicate calcareous layor. The zooecial apertures only are visible (soe. ap.). (N-P after 

 Robertson, 1910.) 



