12 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I40 



Mesopores are common, have walls comparable in thickness with 

 zooecia, and are generally without diaphragms. 



Discussion. — Anaphragma is described in the literature as agreeing 

 in all essential respects with Batosioma, except for very few dia- 

 phragms in zooecia and mesopores and crenulated zooecial walls in 

 the endozone. The phyletic histories of Anaphragma and Batostoma 

 are not known at present, so the relationships between the two genera 



Table 3. 



-Summary of generic characters distinguishing 

 Anaphragma aiid Batostoma 



Structures in 

 common 



Endozone 



Batostoma 

 .Uniformly thin and granu- 

 lar 



Exozone wall laminae . .V-shaped pattern 



Anaphragma 

 Variable in thickness, lam- 

 inated with visible zooecial 

 boundaries 



U-shaped, rarely V-shaped 

 pattern in older growth 

 stages 



Zooecial boundaries Well defined throughout Obscured in older growth 



stages 



Amalgamate, except in a 



few zooecia in youngest 

 growth stages 



Laminated material com- 

 parable in thickness with 

 zooecia throughout 



Zooecial walls in tan- 

 gential view Integrate 



Mesopore walls 



Acanthopores 



Laminated material lacking 

 in earlier growth stages, 

 generally thinner than that 

 of adjacent zooecia in la- 

 ter stages 



, Generally filled with trans- 

 parent calcite and in many 

 species sides are notched. 

 Diameter not greatly con- 

 trolled by growth stage 



Laminated and obscure in 

 longitudinal sections. Di- 

 ameter largely controlled 

 by growth stage in t3rpe 

 species 



must be evaluated on morphologic comparisons alone. Further sec- 

 tioning of the cotype suite and topotypes of A. mirabile indicate 

 that the only comparable character the two genera share, as the 

 genera are presentl)^ understood, is a distressing external homeo- 

 morphy, as witnessed by five previously unsectioned specimens of 

 Batostoma sp. in the cotype suite of A. mirabile. Table 3 summarizes 

 the generic descriptions of structures that the two genera have in 

 common. It is not impossible, of course, for one of the generic stocks 

 to have developed from the other, but on the basis of our limited 

 data the external homeomorphy seems fortuitous and there is no evi- 



