V. 



NOTES ON PALEOZOIC FOSSILS. 



BY AUG. F. FOKRSTE. 



CAMBRIAN. 



MiCRODiscus PUNCTATUS. Salter. 



{Plate XIII, Fig. 5.) 



This species was described by Salter, (Qaart. Journ. Geo!. Soc, 

 1864,) from the Lingula-flags of Wales, at Porthy-Rhaw. The head 

 is semi-circular and the margins at the postero-latcral angles are slight- 

 ly bent out again, forming almost a right angle with the posterior mar- 

 gin. The margin around the lateral and anterior portion of the head 

 has an elevated border at the edge, which is cut transversely by nu- 

 merous short grooves, giving it the appearance of a row of minute, 

 closely set tubercles. The lateral lobes do not approach very closely to 

 one another in front of the glabella, leaving quite a distinct vdcant space. 

 The glabella terminates posteriorly in a long spine. One of the ac- 

 companying figures, enlarged, represents the spines as equalling the 

 length of the head; another, drawn natural size, could under no cir- 

 cumstances be considered longer than two-thirds of the head, and in 

 fact is drawn only half as long. This would suggest that the spine of 

 the enlarged figure is overdrawn, or that it was of an exceptional 

 length. The middle lobe of the pygidium is said in the description to 



