NO. 5 



ORDOVICIAN BRYOZOA BOARDMAN 



II 



The axial ratio is the ratio of the diameter of the endozone to the 

 corresponding branch diameter. 



Table i. — General measurements 



Maximum Minimum 



Diameter of zoarium p.i 4.4 



Diameter of endozone 5.1 2.5 



No. zooecia in 2 mm. (longitudinal direction) 6^ 5 



Average major axis of zooecial void per fragment. . . 0.30 0.23 



Acanthopores per zooecium 3.5 0.6 



Table 2. — Ontogeny 



Average No. 



diaphragms in Width of 



zooecium exozone 



1-2 I.2-I.6 



3 2.3 



5 2.2-2.5 



6 2.6-2.8 



8 3.3 



9 4-4 



12 4-8 



Axial ratio 



0.64-0.74 



0.60 



0.56-0.67 



0.49-0.56 



0.57 

 0.52 

 0.44 



Genus ANAPHRAGMA Ulrich and Bassler 



1904. Anaphragma Ulrich and Bassler, Smithsonian Misc. Coll., vol. 47, No. 



1470, p. 49. 

 191 1. Anaphragma Ulrich and Bassler, Bassler, U. S. Nat. Mus. Bull, yy, p. 297, 

 1920. Batostoma {Anaphragma) Ulrich and Bassler, Vinassa de Regny, Atti 



Soc. Ital. Sci. Nat., vol. 59, p. 226. 

 19353. Anaphragma Ulrich and Bassler, Bassler, Fossilium Catalogus, I : Ani- 



malia, pars 67, p. 46. 



Type species. — Anaphragma mirabile Ulrich and Bassler, 1904, by 

 original designation. 



Emended definition. — Zoaria are ramose. Zooecial walls in endo- 

 zones range from straight to crenulated, are laminated, and gen- 

 erally display dark zooecial boundaries. In the exozone, laminae of 

 zooecial walls generally form a U-shaped pattern in longitudinal sec- 

 tions, but a V-shaped pattern is common in walls of early exozones 

 and occurs throughout the length of zooecia in some zoaria. Thin, 

 complete diaphragms are sparsely distributed, one to several in a 

 very few zooecia; most zooecia completely lack diaphragms. 



In tangential sections, zooecial walls are generally amalgamate, 

 but can be integrate in appearance. Laminated acanthopores are 

 common; their size can be extremely variable within a species. 



