NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
49 
5, P), as in Porella contract a, new species, Enoplostomella synthetica 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, II). 
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-. 
A x 20 
B X 20 
C x 20 
D 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 until the number at the 
exterior (F). 
G, H. Hippodiplosia magniporosa, new species, X 20. Views showing that the tremocyst (G) 
may be detached from the subjacent olocyst (H). 
forations of the latter are alone visible. At the zoarial surface (fig. 6 , 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 (fio-. 6 . G) 
which seem to unite the tremopores among themselves are evidently the intersections 
of the different calcifications. 
Tubules. — The tubular tremopores, when they are quite long, constitute the 
tubulae. They are frequent in Myriozoum , Acroporidae , Porella , etc. Waters 
E x 20 
F x 20 
G x 20 
Fio. 5. — Structure of the tremocyst. 
55899— 19— Bull. 106 4 
