ORDER IT 



CYCLOSTOMATA 



327 



families Ceiamopoi idae and Fistuliporidae, which were fornierly assigned to tlie 

 Trepostouiata and latterly to tlie Cyclostoniata. Tliey agree witli tlie Trepostoniata 

 in liaving well-delined ininiature and niature zones bnt their niinntely poious walls 

 of irregniarly laniinated tissiie, large mural communication pores and fmally, ooccia 

 typical of the Cyclostoniata seem to ally tliem more closely witli tlie latter order. 

 Tills suborder is possibly the Paleozoic representative of the Cerioporina. 



Family 16. Oeramoporidae Ulrich. 



Zoaria variable; maculae or Clusters of mesopores and of zocecia, larger than the 

 average, occur at regulär intervals. Zocecial apertures usually oblique, of sub-triangular, 

 ovate or polygonal form; lunarium present, appearing at the surface as a prominent 

 overarching hood, or as a slightly elevated portion of the margin, of crescentic form 

 with the ends projecting more or less into the aperture. Mesopores or interstitial cells 



I Hi 



Fio. 461. 

 a, Ceramopora spongiosa Bass. Tangential section, 20/j, 

 showing mural pores, 2oyj. d, Crepipora incra.tsata Bass. 

 (after Bassler). 



h, c, Anolotichia rhombiai Bass. Vertical sections 

 Vertical section with ovicell-like structures, '^^/i 



generally present, always irregulär, and usually without diaphragms. A few horizontal 

 diaphragms often present in the zocecial tubes. Walls minutely porous, composed of 

 intimately connected and irregularly laminated tissue. Large mural communication 

 pores sometimes present. Ordovician to Devonian. 



This is one of the largest and most iinportant of the families of Paleozoic Bryozoans, and 

 is especially common in the Middle and Upper Ordovician. The 



earliest forms resemble Berenicea and Apsendesia; while Ceramo- -^Si^^SÄi^^Sli^l^ * 

 porella, Chiloporella, and especially Favositella, may be regarded fWmamiWnl^im'i 

 with reasonable confidence as the progenitors of the Fistuliporidae. 

 At any rate the connection between the two families is so intimate 

 as to forbid any wide Separation. 



Ceramopora Hall (Fig. 461, a). Discoidal, free, lamellate, 

 massive or parasitic. When free, under surface with one or 

 more layers of sniall irregulär cells. Zooecia opening on the 

 Upper surface, large, irregulär, oblique, imbricating, and radially 

 arranged about the depressed centre. Mesopores irregulär, short, 

 numerous. Large communication pores in walls of both zooecia 

 and mesopores. Ordovician to Devonian. 



Ceramoporella Ulr. (Fig. 462). Zoaria encrusting. Zocecial 

 tubes short, walls thin, apertures more or less oblique, hooded, 

 commonly of oval sliape. Mesopores abundant, often completely isolating the zocecia, 

 Ordovician and Silurian. 



Fl(i. 4C2. 

 Ceramoporella dislincta 

 Ulrich. Lowor Trenton, 

 Minnesota. Surface of para- 

 sitic expansion, i'-'/i (after 

 Ulrich). 



