XXXIV 



BRITISH GRAPTOLITES. 



similar to or identical with B. Geinitzianus. He also gives a diagnosis of the new 

 genus Dictyonema, from which it will be seen that he was as yet uncertain as to 

 the zoological affinities of this form. He writes, " The general structure of this 

 coral is very similar to Fenestella. The branches consist of a black film envelop- 

 ing a semi-calcareous or corneous interior, and they have the appearance and 

 texture of Graptolites, to which they are doubtless closely allied." It has very 

 little, if any, true relation with Gorgonia, to which it was previously referred; it 

 " possesses no positive characters by which it can be identified, either as Bryozoa or 

 true corals." Two new species of this genus are described and figured by him — (3) 

 D. gracilis and (4) D. retiformis. He found also a specimen of a new genus 

 however, probably not a Graptolite. 



In the same year (1852) Barrande replied to the observa- 

 tions and conclusions made by Suess on " The Bohemian 

 Graptolites." 



As regards Betiolites, Barrande refuses to accept Suess' 

 interpretation of its structure, believing that the apparent 

 facts observed were due to the bad state of preservation of 

 the specimens. He argues strongly against the validity of 

 Suess' genus Petalolithus, and his species Bet. grandis, Petalog. parallelo- 

 costatus, Gr. ferrugineus, Gr. dubius, Gr. Isem*, Gr. falx, Gr. armatus, and Gr. 

 Subsequent investigators agree with Barrande in most of these 



Inocaulis, which is. 



1852. 



Barrande, 



" Eiuige Bemerkungen 



iiber die Abhandlung 



des Suess," ' Jahrb. der 



k. k. Geol Keicb.au- 



stalt.' 



Barrandei. 

 contentions 



1853. 



Salter, 



" Description of a New 



Species of Graptolite, " 



' Quart. Jouru. Geol. 



Soc' vol. ix. 



1853. 



Bibeiro, 



" On the Carboniferous 



and Silurian Forma- 

 tions of the Neighbour- 

 hood of Bussaco," 

 ' Quart. Journ. Geol. 

 Soc.,' vol. ix. 



A new Graptolite species was described in 1853 by Salter, 

 from the Hudson River group at Lauzon Precipice, under the 

 name Gr. caduceus. Two species, however, are actually 

 figured by him under this name, the one being Tetragraptus 

 serra of Brongniart, and the other the Didymog. gibberulus of 

 Nicholson. 



In 1853 Ribeiro recorded Gr. ludensis of Murchison 

 from the upper division of the Silurian of Portugal, probably 

 from the rocks corresponding with those of the Wenlock 

 formation of England. 



1853. 



Richter, 



" Thuringische G-rapto- 



lithen," 'Zeit. d. 



Deutsch. Geol. Gesell.' 



Bd. v. 



A third paper by Richter on "Thuringische Grapto- 

 lithen " was published in 1853. In this paper he proposes 

 the following classification of the Graptolites, which is 

 considerably more detailed than the one previously given by 

 him in 1850. 





