266 



MOLLUSCOIDEA BRYOZOA 



SUB-KINGDOM v 



opening on the two opposite sides of plates. Depressed interspaces occupied by inter- 

 stitial cells. Cretaceous. 



? Multicavea, d'Orb. 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 Trepostomata, but, as a rule, may 

 be readily distinguished by the complete amalgamation and porous nature of their zooecial walls. 



Ceriopora, Goldf. (Ceriocava, d'Orb.), (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, etc., d'Orb), (Fig. 

 433). Zoarium variable, gener- 

 ally ramose, sometimes com- 

 posed of several layers of tubes. 

 Apertures rounded, the peristome often slightly raised. Interstitial tubes numerous, 

 angular, usually surrounding the zooecia completely, their orifices closed when perfect. 



A C 



FIG. 432. 



Ceriopora spongites, Goldf. Greensand ; Essen. A, Zoarium, 1/1- 

 B, C, Upper and lower sides, enlarged. 



FIG. 433. 



Heteropora pustulosa, Mich. Great Oolite ; Ranville, 

 Calvados (after Haime). A, B, Zoarium, i/j. C, Ver- 

 tical section. D, Upper surface, enlarged. 



FIG. 434. 



Neuropora angulosa, Goldf. sp. Upper Jura; 

 Oerlingen, near Ulm. A, Natural size. B, Portion 

 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, 

 and Tertiary. 



Like the preceding, but growth-habit encrusting. Cretaceous 



