NORTH AMERICAN EARLY TERTIARY BRYOZOA. 



49 



5, /O) as in Porella contracta, new species, Enoplostoniella synthctica Canu and 

 Bassler, 1917, etc. 



The tremocyst is generally intimately united with the subjacent olocyst; 

 in some cases it is clearly detached (figs. 5, G, 11} . 



In tangential sections the size of the tremopores depends on the position of 

 the plane of the section. In the vicinity of the olocyst (fig. 6, A) the small per- 



20 



F x20 

 FIG. 5. Structure of the tremocyst. 



H x20 



A, B. Stomachetosella crassicollis Canu and Bassler, 1917. Orifices of the funnel-shaped 

 tremopores as seen in the interior (A) and at the exterior (B). X 20. 



C, D. Porella crassoparies, new species. Orifices of the tubular tremopores. X 20, in the 

 interior (C) and at the exterior (D). 



E, F. Enoplostomella synthetica, new species. Views, X 20, showing coalescence of the tremo- 

 pores, the number of which in the Interior (E) does not correspond with the number "at the 

 exterior (F). 



G, H. Hippodiplosia magniporosa, new species, X 20. Views showing that the tremocyst (G) 

 may lie detached from the subjacent oloeyst (H). 



f orations of the latter are alone visible. At the zoarial surface (fig. C. D) the 

 tremopores have their normal diameter. It is quite frequent to find thus in the 

 same, section the olocyst and the tremocyst (fig. 6, B}. The reticulations (fis. 6, C) 

 which seem to unite the tremopores among themselves are evidently the intersections 

 of the different calcifications. 



Tubules. The tubular tremopores. when the}' are quite long, constitute the 

 tubulae. They are frequent in Myriu-oum. Acroporiduc, Porella, etc. Waters 



55899 19 Bull. 106 4 



