80 



BULLETIN 11, XJN"ITE]> STATES ISTATIONAL MUSEUM. 



maculae composed entirely of mesopores are present at intervals of 

 5 mm. A portion of a macula with several zooecia and their interven- 

 ing mesopores is shown on plate 6, figure 2. A lunarium occupying 

 about one-fifth of the apertural wall is present, but it is little elevated 

 and is hardly distinguishable either at the surface or in thin sections. 

 An average zooecium is 0.40 mm. in diameter and three may be counted 

 in a distance of 2 mm. 



The essential internal characters are believed to be shown in the 

 accompanying figures. After leaving the immature region, which, 

 as in other incrusting or lamellate ceramoporoids, is quite short, the 

 zooecial walls thicken and numerous connecting pores are developed. 



Fig. 21.— Ceeamopora inteecellata. a, edge view of the fragmentary type, XI; 6 and c, tangen- 

 tial SECTION, X20, AND A PORTION", X35, EXHIBITING THE INDISTINCT LUNARIUM AND CONNECTING PORES; 

 d, VERTICAL SECTION, X20, THROUGH ONE LAYER OF THE ZOARIUM. LyCKHOLM LIMESTONE (Fl), 

 HOHENHOLM, ISLAND OF DAGO, ESTHONIA. 



A few thin diaphragms are inserted in both the zooecial tubes and the 

 mesopores. The connecting pores are equally conspicuous in the 

 tangential section, where also the lunarium may be detected as a 

 slight thickening of the posterior portion of the zooecial wall. 



The lamellate growth, large, angular zooecia, isolated by numerous 

 mesopores, and the large maculse, are characters so different from 

 other species of Ceramopora that comparison is unnecessary. 



Occurrence. — Apparently rare in the Lyckholm limestone (Fl) at 

 Hohenholm, island of Dago. 



Holotype.—C^t. No. 57191, U.S.N.M. 



A thin section of the type-specimen is in the collections of the 

 British Museum. 



