254 BULLETIN 11, UNITED STATES NATIONAL MUSEUM. 



central opening or lumen of the acanthopores and the wall structure 

 of adjoinmg zooecia are likewise well marked. This structure of the 



Fig. 146.— Oebipoea distincta. a, tangential section, X2D, illustrating the usual structures 

 noted; b, vertical section, X8, through a portion of a zoarium; c, small portion of the same 

 section, X20, showing structure of walls and acanthopores. Jewe limestone (D1), Baron 

 Toll's estate, Esthonia. 



acanthopores and of the zooecial walls is essentially the same as in 

 other Batostomellidse, although the uniform diameter of the zocecia 



and absence of macu- 

 lae are conspicuous 

 points of difference. 

 The same characters, 

 in addition to the ab- 

 sence of diapliragms, 

 are also well shown in 

 vertical sections. 



The discoid zoarium, 

 exceptionally large 

 zooecia, numerous 

 large acanthopores, 

 and the absence of 

 maculae and dia- 

 phragms, are charac- 

 ters which will cause the present species to be recognized without 

 difficulty. 



Fig. 147.— Oebipora distincta. a, tangentul section, X20, m 



WHICH THE STRUCTURE IS WELL PRESERVED; 6, A PORTION OF A 

 ZOCECIAL WALL, X35, EXHIBITING THE DETAILED STRUCTURE OF THE 

 ACANTHOPORES. ThE LARGE CENTRAL LUMEN AND THE GRANULES 

 OR TUBULES OF THE ACANTHOPOEE WALL ARE CLEARLY SHOWN. 

 CHASMOPS LIMESTONE, NEAR BODAHAMN, ISLAND OF GeLAND. 



