Eevietcs — Canadian Palceontology. 183 



regional distribution is also very considerable : it extends from the 

 shores of the Gulf of St. Lawrence to the Saskatchewan River. 

 Another species, widely distributed in time and space, is Lyellia 

 affinis, occurring in the "Hudson River and Niagara formations, 

 in the four divisions of the Anticosti Group, and in the Lower 

 Helderberg Group," and ranging from the Island of Anticosti to 

 the Saskatchewan River. 



The detailed descriptions of the species and their mutual relations, 

 distribution, and synonymy are all worked out by the author with 

 great care, and he seems to have sounded his authorities at all points. 



Though in respect to the classification of the Palaeozoic corals 

 we are, and perhaps shall ever be, on very debatable ground, yet 

 it may not be amiss to take a survey of our present position in the 

 light of the more recent attempts made in this direction. Haeckel 

 (" Systematische Phylogenie der Wirbellosen Thiere ") includes in 

 his class Scyphopolypi the fossil Cnidarians, such as the Favositidse, 

 Chaetetida3, Auloporidee, Halysitidse, etc., which built the coral reefs 

 of the Silurian, Devonian, and Carboniferous seas, and are generally 

 assigned to the Tabulata. Nicholson, discarding the latter group 

 as originally constituted, as containing an incongruous assemblage 

 of forms, places the Favositidce, Syringoporida?, and Thecida3 in the 

 Madreporaria Perforata, while the Helioporidae, Heliolitidge, Haly- 

 sitidse, Cheetetidai, and AuloporidjB are referred to the Alcyonaria 

 (" Manual of Palceontology," Nicholson & Lydekker, vol. i). 

 Von Zittel, in his " Grundziige der Palasontologie," while affirming 

 that the greater number of the t^'pical Tabulata (Favositidas, 

 Syringoporidje, Halysitidse) show close relationship to the Hexa- 

 corallia, concludes that any definite decision as to their systematic 

 position seems to be unattainable. On this ground, though retaining 

 them as a suborder of the Madreporaria, he relegates them as an 

 appendix to the Hexacorallia, and places Heliolites in the Octocorallia 

 (Alcyonai'ia), its generally accepted position. 



The uncertainty i-egarding the zoological status of the various 

 groups enumerated above (excepting perhaps the Heliolitidte) is not 

 likely to be dispelled, unless evidence is forthcoming in the shape 

 of a living reef-building coral whose affinities with the fossil reef- 

 builders of the favositoid and other kindred types will satisfy the 

 most searching investigation. Even the remarkable discovery by 

 Mr. J. J. Quelch ^ of a living coral (Moseleija) of Cyathophylloid 

 affinities does not seem to have carried with it evidence of such 

 a convincing character as to shake the position of the Rugosa 

 (or Tetracorallia) as a distinct group. 



Much light is thrown upon the structure and affinities of the 

 Heliolitidce in a recent and valuable contribution to the subject by 

 Professor Lindstrom (Kong. Svenska Vetenskaps-Akad. Handl., 

 Bd. xxxii, No. 1). It is noticeable that the genus Lyellia, M.-E. & 

 H., is rejected by Lindstrom on account of its similarity to 

 Propora, M.-E. & H. 



» Ann. Mag. Nat. Hist., vol. xiii (1884), p. 293 ; " Challenger " Reports, vol. ivi 

 (1886), p. 110 ; see also Nicholson, in "Manual of Pala;ontology," Nicholson & 

 Lydekker, vol. i (1889), p. 274. 



