and species of Silurian Radiata. 285 



P alaopor a "i favosa (M'Coy). 



Sp. Char. Corallum forming irregular rounded masses formed of 

 prismatic tubes, opening as polygonal shallow cells on the 

 surface (averaging \~ line in diameter in limestone, and 

 about 1 line in sandstone) ; the dense narrow interspace or 

 thick boundary-wall of the cells formed of one, or in places 

 two rows of small cells ; concave bottom of the stars very ob- 

 scurely radiated with twelve irregular, rugged, nearly obsolete 

 lamellar projections, scarcely distinguishable from a few inter- 

 mediate granules, a small papillary axis in the centre : vertical 

 section, clear open space of the tube, \ to \^ hne in dia- 

 meter, separated by thick vertical walls (or very narrow dense 

 interspaces of one or two rows of cells), traversed by strong 

 distant horizontal, or slightly concave diaphragms, varying 

 from the diameter to little more than half the diameter of the 

 tubes apart. 



It is vei-y probable that this coral should form the type of a 

 particular genus ; the polygonal cells very narrow, dense inter- 

 spaces, apparent absence of the circular tube of the cells, and 

 small central axis, distinguish it from the other species of Pal<eo- 

 pora. The large masses preserved in limestone are singularly 

 like Favosites Gothlandica, the surface showing apparently the 

 same sized and shaped polygonal hollow cells, with strong divi- 

 sional walls, and the rough vertical section showing apparently 

 prismatic tubes with distant diaphragms ; a sharp eye or a lens 

 however will detect the cellular structure of the divisional walls, 

 and careful search will show the radiation, &c. of the cells; 

 this is most distinct in a polished horizontal section. Spe- 

 cimens preserved in the fine sandstone present a very different 

 appearance, forming small fig-shaped masses covered with hexa- 

 gonal nearly smooth or very minutely granular convex or con- 

 cave casts of the cells, with a distinct axal puncture in the centre 

 of each. I have however connected them satisfactorily, though 

 with diflSculty, with the more perfectly preserved limestone ex- 

 amples. 



Extremely abundant in the calcareous schists and limestone 

 of Craig Head ; Girvan ; and in the fine Caradoc sandstone of 

 Mulock quarry, Dalquorhan. 



Fistulipora decipiens (M'Coy). 



Sp. Char. Corallum forming hemispherical or subcylindrical 

 masses 3 or 4 inches in diameter, concentrically wrinkled at 

 bascj cell- tubes straight, subparallel, with moderately thick 

 walls, leaving clearly defined circular smooth-edged, cells in 

 the transverse section, very regular in size and disposition. 



