of the Varhoniferous Period. 9 



They are both from the lowest carboniferous shales of Cultra, 

 Holljrwood, county Down, Ireland. 

 (Col. Mr. Griffith at Dublin.) 



Coccosteus ? cai'bonarius (M'Coy) . 



Sp. Char. Mesial (ventral?) plate very narrow; sides converging at 

 an acute angle, apex rounded ; mesial keel obtusely rounded, 

 height in the middle one-fourth of the width ; surface closely 

 covered with rounded polished tubercles, varying from one- 

 fourth to one-half of a line in diameter (generally the latter), 

 each surrounded at its base by a little, closely applied, milled, 

 or radiatingly sulcated collar ; the intervening flat space 

 faintly striated, and generally traversed by a small, smooth 

 ridge which winds irregularly between the more distant tu- 

 bercles. 



The character of the sculpturing determines the reference of 

 this species to either Coccosteus or Asterolepis, but as no lozenge- 

 shaped plate similar to the central inferior one of Coccosteus has 

 yet been demonstrated in Asterolepis, I think the reference, with 

 a mark of doubt, to Coccosteus is most correct, a view which is 

 also strengthened by the small size of the tuberculation. The 

 genus has not hitherto been found out of the old red sandstone. 

 The specimen above described being perfect only at one end, 

 might be taken for the pointed posterior extremity of the dorsal 

 plate of a Coccosteus ; but as there is no indication of the little 

 fossa invariably found near the termination of the mesial keel of 

 that plate, it most probably belongs to the under side of the 

 body. The prominent circle at the base of the tubercles, like the 

 spine-basis of a Cidaris, strongly reminds us of the Asterolepis spe- 

 ciosa, but the tuberculation is very much smaller. The inter- 

 tubercular salient line or ridge does not occur in any Pterichthys, 

 Coccosteus or Asterolepis I am acquainted with. A second spe- 

 cimen, a portion of a flat plate from some other part of the 

 body, shows the same size of tubercles and style of ornament, 

 but rather more crowded in some parts and with wider spaces in 

 others ; one or two of the tubercles also, instead of being smooth 

 and polished, show a faint, flexuous radiating striation from the 

 centre to the thickened milled base. The width of the ventral 

 plate at 1:^ inch from the point is only 1 inch, the sides con- 

 verging straight to the apex from this distance. 



Both examples are from the carboniferous limestone of Ar- 

 magh. 



(Col. Capt. Jones, R.N., M.P.) 



Asterolepis verrucosa (M^Coy). 

 Sp. Char. Surface of plates closely covered with prominent, oval. 



