I 72 FREDERICK W. SARDESON 



than tabulae, hemisepta, acanthopores, communication pores, etc. 

 Moreover, tabulae characterize the Monticuliporoidea and true 

 pores the Bryozoa. One cannot assert that no bryozoons have 

 tabulae but they probably do not. The superimposition of cells 

 frequently occurs in monticuliporoids and in bryozoons, but forms 

 a recognizably distinct structure from that of the tabulated cell 

 proper. One finds, again, many descriptions of pores in Monticuli- 

 poroidea but none recognizably like those in Bryozoa, which run 

 direct, transverse, through the cell wall as communication pores. 

 The supposed pores parallel the cell walls and do not end in the 

 cell, and if they were demonstrably pores, their difference would 

 rather serve to separate the group from true Bryozoa. They are 

 not pores in most cases. In case of the reticulate cryptostomata 

 one might not wish to deny that pores could exist, but yet their 

 existence is notably only in the mesopore space or outside the 

 autocell wall, and might be interpreted like the minute porous- 

 ness of some corals (Tubipora) due to living cells remaining in 

 the stereom, rather than as canals. 



SUMMARY 



Briefly reviewed the Monticuliporoid zoarium consists, in 

 the first instance of monomorphic tabulated cells, differing from 

 the extinct Oiaetetes corals in the cell increase being less often 

 by fission than budding. In the second instance, the young 

 closely tabulated cells develop with a retarded or mesopore 

 stage preceding full size growth. In the third, many cells 

 appear to be permanently mesopores, autocells however arising 

 from mesopores. Some autocells displace several mesopores in 

 their rapid growth expansion and the mesopores are either dis- 

 tinct or their bounding walls imperfect and tabulae vesiculose. 

 This development and its minor features is paralleled in living and 

 fossil Alcyonarian Tabulate compound celled corals. In the 

 fourth instance the cells are shortened, and the mesopores or 

 interstitial space filled solid either by superimposed tabulae or 

 hy thickened bounding walls : cells with few or no tabulae or 

 filled : Cryptostomata. 



