NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
83 
Cicatrix of the ovicell- -m- 
Cryptocyst 
Gymnocyst (tremocystal ) 
Mural rim 
Opes ium- 
Interzooecial avicularium . 
Pivot 
Orifice of ovicell- 
Prlmoserial zooeciom 
Blind( sealed ) zooecium 
— Olocyst 
Trace of spine 
---Mural rim of inner zooecium 
Regenerated zooecium 
_-Front,al or dependant avicuiarium 
Gymnocyst (olocystal) 
..Ovicell 
E' 
p ' S d 
C x20 D 
Fig. 23. — Structure of the Membraniporae. 
A. Sketch showing terminology. 
B. Acantliodesia ' savartvi Audouin, 1826. Drawing showing structure, X 85. (After 
Waters, 1913.) m, mesenchymatons filaments; p, polypide in which histolysis has commenced; 
s, septula. 
C. Alderina nodulosa, new species. View of zooec-ia, X 20. i, impression corresponding to 
lucid spot ; ov, ovicell ; sd, distal septula ; si, lateral septula. 
D. Antropova granulifera Hindis, 1880. View of the back of a zooecium, X 145. (After 
Norman, 1903.) a, openings resulting from the avic-ularia; d, lb, lucid bay; Is, lucid spot. 
E. Membraniporina ( Biflustra ) fUibellata D’Orbigny, 1852. Cast of the interior, after de- 
calcification, X 45. (After Beissel, 1865.) sd, distal septula; si, lateral septula; z, zooecium. 
The communication pores between the zooecia, here much enlarged, have the aspect of 
small canals. They serve as passage for the mesenchymatous fibers. 
