NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
677 
Fig. 219. — Family Heteroporidae Pergens and Meunier, 1SS6. 
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, 1879. E. Zoarium, natural size. F. Portion of the sur- 
face, enlarged. (After Busk, 1879.) 
G-P. Heteropora pelliculata Waters, 1S79. 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. J. 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 (zoe. ap .) and the apertures of the interstitial canals (mesopores) (inter, 
can.). P. Portion of the surface of a colony, X 40, in which the interstitial canals are covered 
by a delicate calcareous layer. The zooecial apertures only are visible (zoe. ap.). (N-P after 
Robertson, 1910.) 
