CARBONIFEROUS FOSSILS OF IRELAND. 189 



LiTHODENDRON PAUCIRADIALIS. M'Coy. (PI. XXVII. fig. 7). 



Sj). Ch. — External tube smooth, one-sixth of an inch in diameter, slightly flcxuous, parallel, often coa- 

 lescing, branches few ; lamcllx, ten or eleven within, twenty or twenty-two without ; an internal tube uniting 

 the lamella, within whicli a small crenulation, or radiating set of lamellae appear, one between each of the 

 large ones. 



Tliis differs from all the known species of Lithodendron in the small number of the principal lamella;, or 

 those which reach the centre; externally it differs from the L. fasciculatuin in its smooth svu'face; from the L. 

 affine {longiconicum) in the smaller diameter of the tube, and from all the species in its peculiar mode of branch- 

 ing and crowded, nearly parallel mode of growth. 



Lithodendron sexdecimale. Phil. 



Lithodendron sexdecimale. Phil. Geol. York. 



Sp. Ch. — Tube small, slightly flexuous, loosely branched; surface generally smooth; mesial lamellae six- 

 teen, with curved, vertical dissepiments. 



This pretty species is the smallest of its genus found in the Irish limestone, the tubes being rarely thicker 

 than a crow-quill ; the surface is sometimes finely striated, but generally smooth ; it forms masses of considera- 

 ble size, but is a much rarer and more local species than any of the foregoing. Diameter of tubes one line. 



Lithodendron sociale. Phil. 



E. Madreporites duplicata. Mart. Pet. Derb. ? — Lithodendron sociale. Phil. Geol. York. 



Sp. Ch. — Tubes thick, close, frequently adhering laterally to each other; surface with obtuse, waving 

 longitudinal strige, and concentric wrinkles ; axis ovate ; radiating lamella, about sixty-four, alternately longer 

 and shorter. 



Tills is the largest species of the genus, and from its curious habit of the tubes occasionally adhering late- 

 rally to each other, so as to give them an angular contour, it evinces an approximation to the genus Litho.s- 

 trotion ; the longitudinal stria; are thick and obtuse ; diameters of tubes seven or eight lines. 



Syringopora. Goldfuss. 



Harmodytes. Fisch. 

 Gen. Ch. — Coral, formed of vertical, flexuous, cylindrical tubes, anastomosing by transverse tubuli. 



Syringopora bipurcata. Lonsd. 



Syringopora bifurcata. Lonsd. SU. Syst. 



Sp. Ch. — Dlchotomous, branches short, occasionally anastomosing, connected by small, transverse tubull ; 

 surface smooth ; diameter of tubes one line. 



This species is distinguished by its regular dichotomizing. 



Syringopora catenata. Mart. sp. 



Tubiporites catenata. Mart. Pet. Derb Harmodytes parallela. Fisch. Oyct. Mos — Syringopora reticulata. Gold. 



Pet Harmodytes radians. Bronn. Leth. Geog. 



Sp. Ch. — Tubes small, slightly flexuous; connecting tubull placed at regular distances. 

 This delicate species is easily distinguished from the S. geniculata by its straighter, thinner, and more re- 

 gular tubes, it is more nearly allied to the S. ramulosa, but from that it is distinguished by its more regularly 

 placed, transverse tubuH, and much more slender tubes. Diameter of tubes half a line. 



3B 



