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THE CANADIAN JOURNAL. 



NEW SERIES. 



No. XIX.— JANUAEY, 1859. 



ON THE HTPOSTOMA OE ASAPHUS CANADENSIS, AND 



ON A THIRD NEW SPECIES OE ASAPHFS 



EEOM CANADIAN ROCKS. 



BY E. J. CHAPMAN, 



FEOFESSOE OF GEOIOGT AND MINEEAIOGT, UNIVEESITT COLLEGE, TOEONTO. 



JRead before the Canadian Institute, December ISfJi, 1858. 



I. ASAPHUS CAKADENSIS. 



In our recent description of this new species (Canadian Journal, 

 vol. 3, p. 230 ; and Annals of Natural History, July, 1858), we were 

 unable to give any definite information respecting the form of the 

 hypostoma. Since the publication of this description, however, Mr. 

 J. E. Smith, of Toronto, has found a well preserved hypostoma 

 (evidently belonging to the species in question), in the Utica slate 

 of Whitby, in Canada West — one of the principal localities of the 

 species. By the kindness of Mr, Smith, whose zeal in the service of 

 Canadian palaeontology we have already had occasion to acknowledge, 

 we are enabled to lay before our readers a figure of this hypostoma, 

 somewhat enlarged. In its outline, the hypostoma of Asaphus 

 Canadensis, as in all the recognised species of the genus Asaphus, 

 exhibits the well-known fork or " horse-shoe" at its lower or buccal 

 extremity. The upper margin or so-called " base" is partially ob- 

 scured, and the wings, or ascending processes by which the hypos- 



VOL. IV. B 



