On a new Genus of Carboniferous I'ulyzoa. 43 



IV. — Note on a new Provisional Oenus of Carboniferous 

 Polyzoa. By K. Etueridge, Jun., F.G.S. 



[Plate IV. B. figs. 1-4.] 



Hyphasmopora, gen. nov. * 



Polyzoarium dendroid (?), calcareous, composed of small 

 cylindrical stems, often bifurcating. Cell-depressions arranged 

 in linear longitudinal series, more or less separated from one 

 another by a cancellated network or reticulation, forming the 

 interstitial surface, and predominating at one part of tlie poly- 

 zoarium more than at others, presenting a longitudinal zone, 

 devoid, or nearly so, of cell-depressions. The interstitial net- 

 work consists of a series of irregularly formed pores. 



The fragments to which I have provisionally applied the 

 above name consist of small occasionally bifurcating stems, 

 with nearly the whole of the surface occupied by six or more 

 longitudinal rows or series of pyriform and (for the size of tlie 

 organism) large cell-depressions, subaltemating one with the 

 other. The intermediate and remaining portions of the in- 

 terstitial surface, between each longitudinal series and each 

 individual cell, are occupied by small, irregularly formed, but 

 generally elongate pores, forming a reticulated or cancellated 

 network. This is more particularly the case over one part of 

 the surface, generally devoid of cell-depressions, but occasion- 

 ally with a single row running up the centre, or one or two 

 irregularly placed. This space is bounded by the two lateral 

 rows or series of cell-depressions, one occupying each side of 

 the stem. At times the poral reticulation between the longi- 

 tudinal series of cell-depressions is almost absent, or consider- 

 ably reduced, when, the lateral prominent margins of two 

 contiguous series imiting, a dividing ridge or keel is formed, 

 which, when viewed transversely, gives to the cross section of 

 the stem a slightly multiangular appearance. The cell-depres- 

 sions lead upwards and inwards to the true cell-aperture or 

 orifice, considerably smaller than the larger opening, and ap- 

 parently oval in outline. 



The cells are at first vertical, and then curve obliquely up- 

 wards and outwards to the surface, where they open at right 

 angles to the imaginary axis, the pyriform depression in which 



• v(f>a<Tfj.a, tissue or web ; nopos, a passage or pore. [The specimens are 

 in the collection of the Geological Survey of Scotland ; and this descrip- 

 tion is published bv permission of the Director-General of the Geological 

 Survey.^ 



