FISTULIPORIDiE. 



359 



in well-preserved specimens sometimes exhibits a peculiar striated aspect, 

 as if it were finely tubulated. 



The genus Callopora, as maintained by Waagen, must find a place in 

 the immediate neighbourhood of Fistulipora. The typical species of this 

 genus resemble Fistulipora in most respects, but the autopores are, as 

 a rule, without pseudoseptal folds, and the mesopores have complete walls 

 and are furnished with straight tabulae, which do not coalesce to form an 

 interstitial vesicular tissue (fig. 225, B). In some cases, traces of pseudo- 



Fig. 234. — Fistulipora incrustans, from the Carboniferous rocks of England. A, A colony 

 growing on the stem of a Crinoid, of natural size ; b, Broken extremity of the same, showing 

 the thickness of the colony; c, Portion of the surface, enlarged almost twenty times; d. Tan- 

 gential section, similarly enlarged; e, Vertical section, similarly enlarged, a, Autopores; m, 

 Mesopores ; c, Primordial tubes of the colony. (After Nicholson and Foord.) 



septa are present in the autopores, and in one species {Callopora Foordii, 

 fig. 229) these structures are exceptionally developed. Pseudoseptal 

 spines are occasionally present in this genus. The walls of the autopores 

 in Callopora are not specially thickened in the " mature " region of the 

 corallum, as is shown by the structure of the type-species of the genus 

 (Callopora elegaHtula, Hall). Hence, forms like Callopora {?) ramosa, 

 E. and H., of the Ordovician rocks of North America, which have been 

 referred here by Mr Ulrich, must find a place elsewhere, as the autopores 

 become markedly thickened in the peripheral portion of the corallum. 



