PROBLEM OF THE MONTICULIPOROIDEA 1 69 



to a solid axis, 1 details of which may be omitted here, since 

 there is no character in Cryptostomata as also in Trepostomata 

 negative to supposed relation of Monticuliporoidea to Tabulate 

 corals as already discussed, unless, as said, their relation to 

 Bryozoa can be proved. 



In comparing to Cylostomata to which Cryptostomata have 

 been sometimes referred, Stomatapora and Berenicea come first 

 into consideration. Vine referred them to Cryptostomata in 



C D 



AFFINITIES OF MONTICULIPOROIDEA. 



Fig. 2. Diagrams showing : A. Interpreted origin of inferior and superior 

 hemiseptum. a, axial cell stage ; b, turning stage ; c, peripheral stage, hemisepta 

 remaining at points where the relation of zooid and its cell changed most. B. Pro- 

 boscina minnesotensis Ulr., transverse section. X 40. C. Relation of zooids of 

 Bryozoa to their cells, for comparison with D, the interpreted relation in Cryptosto- 

 mata. a, tabulated cell as in Pachydictya; b, cell with hemisepta as in Ptilodictya; 

 c, cell closed by wall-thickening as in same. 



fact. These genera comprise essentially the Paleozoic Cyclosto- 

 mata, and range from Ordovician to Recent times. Stomatopora 

 (e. g., S. inflata H.) forms branching single series of club-shaped 

 prostrate free cells, each arising from under the anterior, larger 

 end of the preceding one, and having a small circular aperture 

 on the anterior upper side. Its walls are said to be minutely 

 porous if well preserved. Stomatopora is not comparable to any 

 of the Monticuliporoidea, but is a key to species called Probo- 

 sciiia or Berenicea. 



Proboscina minnesotensis (Ulr.) forms two, three, or more series 

 of prostrate cells, each arising from under the anterior of the 

 preceding cell of its series. The anterior end is drawn out 

 upwards, making a vestibule, as it is called, bearing the round 

 aperture. The cells appear superficially as immersed in a band 

 of stereom, but thin sections show only compacted, thin-walled 



1 Pachypora, Corallium, etc., see Neues Jarb., Beilb. X, p. 306-312. 



