ORDER II 



CYCLOSTOMATA 



329 



Spatürpora Ulr. (Fig. 468). 

 Apertures irregulär ; 

 luiiariuni scarcely per- 

 ceptible. Mesoporen, 

 wlieii present, cliiefly 

 in iiiaciilae. Inter- 

 spaces often witli large 

 bliint spines (? acan- 

 thopores). Ordovician 

 and Silurian. 



Family 17. Pistuli- 

 poridae Ulricli. 



Zoaria massive, 

 laminar or ramose, the 

 siirface exhihiting at regulär intervals 

 " maculae " or " monticules " com^ 

 of Clusters of vesicles and of zooßcia 

 slightly larger than the average. Luna- 

 rium more or less developed. Zooecial 

 tubes never angular, thin-ivalled, and 

 ivith horizontal diaphragrifis ; apertures 

 closed by perforated operculum. Inter- 

 spaces occupied by vesicular tissue. Gell 

 walls minutely porous. Ordovician to 

 Perinian ; cliniax in Devonian. 



Zoaria Ibrniing thin crusts, especially on Orthoceras. 



Fig. 468. 



Spatiopora aspera Ulr. Cincinnati Group ; Hamilton, O. 

 A, Surface. B, Vertical section. C, Tangential section ; all 

 i-«/i (after Ulrich). 



Waagen, Wentzel and otliers have 

 referred certain merabers of tbis family to the Corals, but tbe reasons for doing so rest 

 obviously upon insufiicient 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, tlius" abundantly proving their Bryozoan nature. 



Fistulipora M'Coy (Didymopora Ulr. ; Dybowskiella 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 

 pyriform, according to the degree 

 in which the lunarium is developed ; 

 interiorly with thin walls, and a 



small number of com plete horizontal . ,. ,. .j, . , 



^ Fistuhpora astnca Ulrich, 



diapliragms. Interspaces smooth or Devonian (Hamilton Group); 



granulär, occupied internally by So?" »/i?' ^''''^' '^^""'"''^^ 



one or more series of vesicles. Rare 



in the Ordovician. Common from Silmian to Lower Car- 



boniferous less frequent in Goal Measures and Permian. 



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

 lunarium obsolete, and zocecial tubes circular in transversa 

 section. Devonian . 



Eridopora Ulr. (Pileotrypa Hall). Zoaria thin, parasitic. 

 Zooecia with oblique, sub-triangular or ovoid apertures. 

 Lunarium very prominent. Silurian to Goal Measures. 



Fit;. 470. 

 Cyclotrypa communis Ul- 

 rich. Hamilton ; New Buf- 

 falo, Iowa. Vertical and 

 tangential sections, i*/i 

 (alter Ulrich). 



