Vol. 67.] PERMIAN TO THE TRIAS IX NOTTINGHAMSHIRE. 107 



as ' probably ' belonging to the highest Permian deposits. In the 

 foregoing list the genera have been arranged in classes, according 

 to the classification adopted by Zittel in his ' Grundziige der 

 Palaontologie ' (1903). 



Many of the generic and specific names have been altered by 

 later palaeontologists ; and the list given would be considerably 

 reduced, if it included only those forms which are generally 

 acknowledged to be distinct species. Thus Kirk by united all the 

 four forms of Schizodus into one species, Axinus obscurus Sow. : 

 which would now become Schizodus obscurus (Sow.), or Myophoria 

 obscura, if, with Prof. Steinmann (1907), we regard Schizodus as 

 inseparable from Myophoria. Similarly, Kirkby considered the 

 two species of Mytiius to be inseparable from Myalina hausmanni 

 Goldf. King (with some hesitation) placed these forms in two 

 species of Mytiius, but Dr. Wheelton Hind (1897, p. 104) seems to 

 infer that they are really Myalina, and adds that 



1 one is seemingly warranted in characterizing Myalina as a freshwater 

 genus.' 



Zittel, in his ' Grundziige' (1903), gives Silurian and Devonian as 

 the range of Myalina, and Trias to recent for Mytiius; while 

 Prof. Steinmann regards Myalina as part of the genus Gervillia. 



Monotis is Triassic only, according to Zittel : Geinitz l made it 

 a subgenus of Avicula. Bakevellia was placed by him as a sub- 

 division of Gervillia, but was accepted as a distinct genus by Zittel. 

 Prof. Steinmann does not mention the name at all, having apparently 

 included it under Gervillia. 



Leda speluncaria Gein. is considered by King to be the same 

 as L. vinti King. The ? Edmondia elongata Howse, recorded at 

 Manchester by Geinitz, would appear to be wrongly named, since 

 the range of Edmondia is given by Zittel as Carboniferous. 



Cleidophorus is stated by Zittel to range from the Silurian to 

 the Devonian. The range in time of Dentalium is given by the 

 same authority as Silurian to recent. 



Geinitz thought that Turbo mancunensis Brown was included 

 in T. helicinus Schl., and that Rissoa gibsoni Brown is probably 

 the same as R. leighi Brown. 



Of the sponge Tragos binneyi King, Dr. Hinde 2 says : 



'The type-specimen, now in the Museum of Queen's College, Gal way, shows 

 no traces of organic structures, and appears to me to be of inorganic origin. 

 It comes from Bradford, near Manchester.' 



The Vermes are, of course, fossils of very indefinite characters. 

 Vermilia is not mentioned by Zittel, and appears to be referred 

 now to Serpula. Geinitz thought that Filograna might be a 

 pteropod : this name, also, seems to be no longer recognized. 



The fish Gyropristis is not mentioned in Dr. A. S. Woodward's 

 * Vertebrate Palaeontology ' ; but, in Woodward & Sherborn's 3 



1 H. B. Geinitz, 1890, p. 551. 2 Gh J. Hinde, pt. ii, 1888, p. 183. 



3 A. S. Woodward & C. D. Sherborn, 1890, p. 91. 



