64 PROCEEDINGS OF THE ACADEMY OP 



arrangement and nearly circular form of its pores, as well as in 

 having a raised longitudinal line between each row of pores, than 

 to any of the known Upper Silurian species. It is a much more 

 robust species, however, with only about the same number of rows 

 of pores, in a branch of twice the breadth of those of that species, 

 while it shows no traces of the transverse bars mentioned in the 

 description of S. fenestrata. Its flattened, nonporiferous, and 

 striated margins are also much more strongly developed. Indeed, 

 no traces of this character of the margins are represented in the 

 published figures or mentioned in the description of that species. 



Although I am not aware that any published notice of the 

 occurrence of this genus in the Devonian rocks has hitherto ap- 

 peared, I have little hesitation in referring this species to the 

 group, since it seems to present all the characteristics assigned to 

 the same. In one respect it differs from some of the species de- 

 scribed under Stictoj)ora. That is, in having the pores a little con- 

 tracted, and nearly circular at the aperture. In this respect, 

 however, it appears to agree with S. fenestrata, the. first species 

 described under that genus ; and Prof. McCoy has shown that this 

 character occurs in British species of Ptilodictya, of Lonsdale, of 

 which it is now generally admitted that Stictopora, Hall, is only 

 a sjnionym, or at most founded on types only subgenerically 

 distinct. 



From the same horizon as that from which the above-described 

 species was obtained, but from a different locality (Whitehouse, 

 Lucas Co.), there is in the collection a foliated specimen more than 

 two inches in breadth, and 4.10 inches long, with broken margins 

 all around. It is split in breaking the rock, so as to expose one 

 side of the strongly wrinkled and striated axis. So far as I have 

 been able to determine from some imperfect remaining portions 

 of the poriferous part, its pores would seem to have the same 

 form, size, and arrangement as the species here described. It 

 may, therefore, possibly belong to the same species, though I am 

 inclined to believe it will be found to be distinct. If so, it may 

 be called P. {Stictopora) lichenoides. 



Locality and jwsition. Sylvania, Lucas Co., and Marblehead. 

 Corniferous limestone. Mr. Gilbert. 



[June 6, 



