Dr. Salter on Lerneonema Bairdii. 85 



fluence of the great diversity of geographical position, or is there, 

 besides, a difference of epoch of formation between these rocks ? 

 The only character which tends to approximate the last two floras, 

 is the relation which both possess to that of the coal formations, 

 of which they appear to be a kind of extract, and of the more 

 recent strata of which they especially remind us. 



As to the plants of the bituminous schists of the Mansfeld 

 country, they are so few in number and appear to have been de- 

 posited under conditions so different, that it is difficult to com- 

 pare them with the other two floras. However, the species of 

 Sphenopteris are extremely alike in these three formations, and 

 perhaps an accurate comparison would establish the identity of 

 several of them : the Pecopteris crenulatus of Ilmenau is perhaps 

 only an imperfect state of the Pecopteris abbreviata of Lodeve ; 

 finally, the species of Callipteris of the Permian rocks and of 

 Lodeve have very intimate relations with each other and with the 

 Callipterides of the coal formation. 



We will add, relatively to the bituminous schists of Thuringia, 

 that several of their fossils appear to be marine plants, the 

 number of which would become far more considerable did we 

 not suppress all the imperfect impressions which have been 

 described as such, and which are merely altered fragments of 

 Ferns or Coniferse. 



[To be continued.] 



VIII. — Description 0/ Lerneonema Bairdii. 

 By Dr. James Salter. 



[With a Plate.] 

 To the Editors of the Annals of Natural History. 

 Gentlemen, British Museum, June 1st, 1850. 



The accompanying sketch and description of a remarkable ani- 

 mal belonging to the order Lerneadse has been lately sent me by 

 Dr. Salter of Poole. It evidently belongs to the genus Lerneo- 

 nema of M. Edwards, but presents some peculiarities which di- 

 stinguish it from the only two species of that genus hitherto 

 fovmd in this country. The want of an apparent head and the 

 possession of only one horn-shaped appendage caused me to fear 

 that that part of the animal, in the specimen from which the 

 drawing was made, was imperfect, a portion of the head having 

 perhaps been torn off in removing it from the herring to which 

 it was attached. In reply however to my inquiries upon that 

 subject. Dr. Salter assures me that there could be no mistake as 

 to the state of the head, as he had examined it very carefully. 



