074 NEW YORK STATE MUSEUM 



p a t u 1 u 8. As the form of the thecae does not pemiit a reference to either of 

 the two last named species, the one having broader and shoi-tei', the otht^r more 

 inclined and curved thecae, it has been with us a question of either ci-eating 

 a new specific term or extending the definition of I), n i ti d u s sufficiently to 

 include these foi-ms. We have preferred the latter, as the two are connected 

 by such easy gradations that it would be impossible sharply to divide them. 

 As, however, in other localities the species is evidently restricted to its typical 

 expression, the fact of the variation calls for recognition, and we propose to 

 designate these larger forms with somewhat less closely arranged thecae as the 

 variety D. nitidus var. g r a n d i s. 



Didymograptus patulus Hall sp. 



Plate 13, figures 8, 9 : plate 14, flgure 7 



Graptolithus patul US Hall. Geol. Sur. Can. Rep't for 1857. 1858. p.l31 

 Graptolithus patulus Hall. Canadian Organic Remains, decade '2. 1865. 



p.71, pl.l, fig.10-15 

 Non Didymograptus patulus Nicholson. Qnar. Jour. Geol. Soc. 1 868. 



24:135 

 Non Did3-mograptu8 patulus Nicholson {pars). Ann. and Mag. Nat. Hist. 



8er.4. 1870. 5:340, pl,7, fig.la 

 Didymograptus patulus Hopkinson. Quar. Jour. Geol. Soc. 1875. 31:644, 



pl.33, %.4a-e 

 Didymograptus patulus Linnarsson. Sver. Geol. Und. Afh. och Upps. 1879. 



ser.C, no.31, p. 5 

 Didymograptus patulus Brogger. Die sil. Etagen 2 and 3. 1882. p.39 

 Didymograptus pa t ul us Herrmann (^ars). Geol. Mag. Dec. 3, 1886. 3:14 

 Didymograptus patulus Matthew. Royal Soc. Can. Proc. and Trans. 1893. 



10:98 

 Didymograptus p a t u 1 u s Matthew. Royal Soc. Can. Proc. and Trans. 1894. 



11:114 

 Didymograptus patulus Guriey. Jour. Geol. 1896. 4:295 

 Non Didymograptus patulus EUes. Quar. Jour. Geol. Soc. 1898. 54:504, 



lig.22, 23 

 Non Didymograptus p a tulus Tornquist. Luuds Univ. Arsskrift. 1901. Bd37, 



Af.2, Nr5, p.l5, pl.2, %.l-6 



