266 MOLLUSCOIDEA—BRYOZOA SUB-KINGDOM V 
opening on the two opposite sides of plates. Depressed interspaces occupied by inter- 
stitial cells. Cretaceous. 
? Multicavea, VOrb. Zoaria ramose, the stems poriferous on all sides, interstitial 
cells composing the greater part. Apertures forming short stellate series disposed at 
close intervals over the surface of the branches. Cretaceous. 
Family 8. Cerioporidae. Busk. 
Zoaria multiform, encrusting, lamellar, bulbous, lobate, digitate, or ramose, composed of 
closely arranged thin-walled tubes. The latter sometimes completely separated by angular 
interstitial cells. Walls of neighbouring tubes thoroughly amalgamated and pierced by 
numerous pores. Trias to Recent. 
The Cerioporidae greatly resemble many of the Palaeozoic 7repostomata, but, as a rule, may 
be readily distinguished by the complete amalgamation and porous nature of their zocecial walls. 
Ceriopora, Goldf. (Ceriocava, WVOrb.), (Fig. 432).  Zoaria encrusting, massive, 
lobate, or ramose, often consisting of two or more superposed layers of tubes. The 
latter are sub-equal, in close 
contact, of one kind only, and 
their round or polygonal aper- 
tures cover the entire upper 
surface of the colony. Very 
abundant in the Alpine Trias, 
sparse in the Jura, but frequent 
again in the Cretaceous. 
Heteropora, Blainv. (Multi- 
cresis, Nodicresis, Zonopora, 
Polytremata, ete., Orb), (Fig. 

Fic. 432. F i 3 
ee 433). Zoarium variable, gener- 
Ceriopora spongites, Goldf. Greensand; Essen. 4, Zoarium, 1/,. . a 
BL, C, Upper and lower sides, enlarged. ally ramose, sometimes com- 
posed of several layers of tubes. 
Apertures rounded, the peristome often slightly raised. Interstitial tubes numerous, 
angular, usually surrounding the zowcia completely, their orifices closed when perfect. 

Fic. 433 Fic. 434. 
Heteropora pustulosa, Mich. Great Oolite ; Ranville, Newropora angulosa, Goldf. sp. Upper Jura ; 
Calvados (after Haime). A, B, Zoarium, 1/3. C, Ver- Oerlingen, near Ulm. «A, Natural size. 5B, Portion 
tical section. D, Upper surface, enlarged. of surface, enlarged. 
They are frequently gathered into clusters and separate the true zocecia into zones or 
patches. Very abundant in Jura and Cretaceous, rare in Tertiary and Recent. 
Heteroporella, Busk. Like the preceding, but growth-habit encrusting. Cretaceous 
and Tertiary. 
