ORDER II 



CYCLOSTOMATA 



329 



Spatiopora Ulr. (Fig. 468) 

 Apertui'es irregular ; 

 Imiariuni scarcely per- 

 cej^tible. Mesopores, 

 when present, chiefly 

 in maculae. Inter- 

 spaces often with large 

 blunt S2)ines (? acan- 

 thopores). Ordovician 

 and Silurian. 



Family 17. Fistuli- 

 poridae Ulrich. 



Zoaria massive, 

 laminar or ramose, the 



Zoaria forming thin crusts, especially ou Orthoceras. 



IS 



Favositella laxaia (Ulr.). 

 B, Vertical section, ^/j. 



Flo. 467. 



Lower Trenton ; Minnesota. .1, Surface, J-*/i. 

 '_', Transverse section, n/i (after Ulrich). 



ABC 



surface exhibiting at regular intervals 

 " maculae " or " monticules " comjwsed 

 of clusters of vesicles and of zooecia 

 slightly larger than the average. Luna- 

 rium more or less developed. Zooecial 

 tubes never angular, thin-walled, and 

 with horizontal diaphragms ; apertures 

 closed by perforated 0])erc;ulum. Inter- 

 spaces occupied by vesicular tissue. Cell 



walls minutely porous. Ordovician to „ . ,^, '' . " ^. „ ,, .,^ 



„ . 1 • • T-. ■ Spatiopora aspera Ulr. Cincinnati Group ; Hamilton, O. 



i'ermian ; climax m Devonian. a, Surface. B, Vertical section. C, Tangential section ; all 



w i^r ^ 1 1 .1, X. »/i (after Ulrich). 



VVaagen, vVentzel and others have 



referred certain members of this family to the Corals, but the reasons for doing so rest 

 obviously upon insuthcient observation. Not only are the members of this family 

 derived from the Ceramoporidae, as noted above, which are undoubted Bryozoans, 

 but some of them possess ovicells, thus abundantly proving their Bryozoan nature. 



Fistulipora M'Coy {Didymopora Ulr. ; Bybowskiella Waag. and W.) (Fig. 469). 

 Zoaria massive, lamellate, more 

 rarely ramose, parasitic or free ; 

 under surface with wrinkled epi- 

 theca. Zooecia sub-radially arranged 

 about the surface maculae ; aper- 

 tures ovoid, sub-triangular or 

 pyriforni, according to the degree 

 in which the lunarium is developed ; 

 interiorly with thin walls, and a 



small number of complete horizontal 



T 1 -t , ^ , Fistulipora astrica Ulrich. 



diapliragms. interspaces smooth or Devonian (Hamilton Group) ; 



granular, occupied internally by ;^^'t''io^"f4,'°' ^°''''^- tangential 



one or more series of vesicles. Bare 



in the Ordovician. Common from Silurian to Lower Car- 



Iwniferous less frequent in Coal Measures and Permian. 



Gyclotrypa Ulr. (Fig. 470). Like Fistulipora, but the 



lunarium obsolete, and zooecial tubes circular in transverse 



, . -p. . ' Pig. 470. 



section. JJevonian . 



7-1 -7 TT1 /T-.-7 . TT nv r, . , Cyclot ry pu comwunis Ul- 



Uridopwra Ulr. {Ftleotrypa Hall). Zoaria thin, imrasitic. rich. Hamilton; New Buf- 

 Zocecia with oblique,' sub - triangular or ovoid apertures. '^^,^- ^^^ % 

 Lunarium very prominent. Siluiian to Coal Measures, (after Uhieh). 



Pio. 469. 



