148 PROCEEDINGS OP THE PALEONTOLOGICAL SOCIETY 



Several papers bearing on mutations were then read, the first of these 

 being the following, which was discussed by Messrs. Ulrich, Grabau, 

 Schuchert, Euedemann, and Loomis, with replies by the author : 



MUTATIONS OF WAAGEN, MUTATIONSRICHTUNG OF NEUMAYR, MUTANTS OF 

 DE TRIES: RELATIONS OF THESE PHENOMENA IN EVOLUTION 



BY HENRY FAIRFIELD OSBORN 



The second paper on mutations, by A. W. Grabau, was withdrawn, so 

 that it could be discussed in the exhibition room in connection with 

 charts and other illustrations. 



SYSTEMATIC RANK OF MUTATIONS AND SUBMUTATIONS IN ORTHOGENETIC 

 SERIES AMONG THE INVERTEBRATES 



BY AMADEUS W. GRABAU 



(Abstract) 



It is shown that mutations and submntations may vary in systematic value, 

 being of varietal specific or even generic rank, in accordance with the degree 

 of fixity attained by the various morphological stages of development in dif- 

 ferent genetic series. 



A second paper by the same author was next in order, but was again 

 withdrawn, so that it could be discussed in the exhibition room, where 

 illustrative charts were available. 



CLASSIFICATION OF THE TETRASEPTATA, WITH SOME REMARKS ON 

 PARALLELISM IN DEVELOPMENT IN THIS GROUP: A STUDY IN 

 ORTHOGENESIS 



BY. AMADEUS W. GRABAU 



{Abstract) 



The paper offers amended and revised classification of the Tetraseptata 

 (Tetracoralla) and shows how many of the common genera of this group are 

 in reality polyphyletic eirculi, and that a recognition of the law of parallelism 

 in development requires a redefining of these genera. 



The final paper of the morning then followed and was discussed by 

 H. M. Ami and Rudolph Euedemann, with replies by the author. 



GUELPH FORMATION OF ONTARIO 

 BY M. Y. WILLIAMS 



(Abstract) 



The Guelph formation of southwestern Ontario, as originally denned, con- 

 sists of about 185 feet of saccharoidal dolomite. From information obtained 



