imperfectly -hnown Species of Corah. 17 



From E. BoiverhanM, E. & H,, the presp.nt species is sepa- 

 rated by the fact that each or the corallites possesses a "well- 

 developed external investment, while the coralkim is not 

 astrffiiform. 



Horizon and Locality. Inferior Devonian, Montjean, 

 Gallois [coll. CEhlert). 



Striatopora pachystoma, Nich. ' 

 (PL I. figs' l-lh.) 



Spec. char. Corallum ramose, composed of cylindrical or 

 subcylindrical branches, which have a diameter of from 5 to 

 10 millims. The corallites are primitively polyclonal, with 

 exceedingly distinct walls, but having the visceral chambers 

 greatly contracted by a secondary deposit of light-colom'ed 

 sclerenchyma deposited in concentric lamellse, the amount of 

 this thickening being greatly increased as the mouths of the 

 tubes are approached (PL I. fig. 1 a). The size of the coral- 

 lites is very variable, the largest ones having a long diameter 

 of about 3 millims. (from wall to wall), while the smallest 

 ones may not be much over a millimetre in width when simi- 

 larly measured. The preservation of the calices in all 

 specimens I have seen is poor ; but they are not surrounded 

 by thin and sharp margins, and tangential sections show that 

 the diameter of the visceral chambers near their mouths varies 

 from a millimetre and a half in the largest tubes to about half 

 a millimetre in the smallest corallites. No septal teeth, or but 

 very rudimentary ridges, are developed on the neck of the 

 tubes. No traces of tabulae are recoi^nizable in lono- sections 

 (PL I. fig. 1 h), but the walls of the tubes are seen to be 

 perforated by a few remote and irregularly-distributed mural 

 pores. 



Ohs. This species is most nearly allied to the Striatopora 

 Linneanaj Billings, of the Devonian rocks of Canada (see 

 Nicholson, Tabulate Cor. of the Pal. Period, p. 100, pi. v. 

 figs. 2-2(7), which it much resembles in its general aspect. 

 It is, however, in general a coarser and more stoutly-built 

 form, and it differs structurally from S. Linneana, Bill., in its 

 want of tabulse and in the fact that the calices are not sur- 

 rounded by a thin polygonal rim. Though the external 

 preservation of the specimens is not good, this much can be 

 made out with certainty — the calices being always bounded by 

 thick walls (PL I. fig. 1), and being in the best-preserved 

 examples surrounded by thickened and raised circular borders, 

 whereas in S. Linneana the calices have sharp-edged poly- 

 gonal borders surrounding the cup-shaped apertures of the 

 tubes. Moreover the present species appears to want the 



Ann. & Mag. N, Hist, Ser. 5. Vol. vii. 2 



