Dr. A. Smith Woodtvard — A Carboniferous Ichthyodorulite. 487 



The dermal tubercles associated with these spines are even more 

 numerous than the latter, especially at one end of the group, and 

 they are of the form known as Petroclus. They are solid, and 

 consist of very porous vasodentine. Their basal face is flat, and 



Figs. 1-S. — Listracantlms Warcli, sp. nov. ; three times nat. size. Middle Coal- 

 measures, Smalltliorne, North Staffordshire. (Collection of John Ward, Esq., 

 F.G.S., Longton.) 



1. Base of spine. 

 2, 3. Middle and terminal portions of spines. 



4. Restored drawing of spine. 



5. Transverse section of spine. 



6, 7. Tubercle, upper and lateral aspects. 

 8. Larger tubercle, upper aspect. 

 Fig. 9. — Fetrodus acutus, Newb. & "Worth. ; upper aspect and lateral aspect (9«) 

 of tubercle, 2\ times nat. size. Carboniferous Limestone, Mjatschkowa, 

 Moscow. (Brit. Mus. No. P. 5,117.) 



when viewed from this aspect they are observed to be usually 

 oval or ovoid in shape, rarely circular. They are irregularly conical, 

 and their height is less than their longest basal diameter. Their 

 apex is smooth and rounded, and their sides are crimped by a few 



