2 12 NEW YORK STATE MUSEUM 



b a m e n s i s assist also in producing a different habit. The axillary angle 

 shows the same variation from an acute to a broader form and the 

 dorsal walls of the branches are joined, as a rule, by a "web" or conchio- 

 linous membrane, as in the British form. In narrow axillary angles this 

 web extends as far as the aperture of the fourth theca of either side ; in 

 wider axillary angles, when present altogether [as in text fig. 235], it forms 

 but a narrow crescent band. 



Elles and Wood in remarking on the direction of growth of the earliest 

 thecae in D. sextans, state that the " Diplograptid " appearance of the 

 proximal end brings that form into close relationship to the Dicranograpti, 

 so that it might be regarded as one of the intermediate forms between 

 Dicellograptus and Dicranograptus. D. moffatensis var. a lab ani- 

 ens is goes still farther in approaching Dicranograptus and quite dis- 

 tinctly points out the path of development of that genus by the approach 

 of the dorsal walls of the bases of the branches and their connection by a 

 web. A further step along this line would be the actual adnation of the two 

 branches and the formation of a septum [see p. 1 1 1]. 



Dicellograptus elegans Carruthers 



Didymograpsus elegans Carruthers. Geol. Mag. 1868. 5:129; pi. 5, fig. 8a, 8d 

 Dicellograptus elegans Hopkinson. Geol. Mag. 1871. 8:24; pi. 1, fig. 3a-e 

 Dicellograptus elegans Lapworth. Cat. West. Scott. Foss. 1876. pi. 4, fig. 87 

 Dicellograptus elegans Lapworth. Belfast Nat. Field Club. Rep't & Proc. 



Apx. 1877. v. 1, pt 4, pi. 7., fig. 8 

 Dicellograptus elegans Gurley. Geol. Sur. Ark. An. Rep't. (1890). 1X92. 



3:414 

 Dicellograptus elegans Gurley. Jour. Geol. 1896. 4:71 

 Dicellograptus elegans Clark. Geol. Mag. Ser. 4. 1902. 9:498 

 Dicellograptus elegans T. S. Hall. Rec. Geol. Sur. Victoria, v. 1, pt 4. 1906. 



P- 2 75, pl- 34, fig- 2 

 Dr Gurley has cited [1896] this species as occurring at Stockport, 

 N. Y., stating that "specimens occur in our Lower Dicellograptus /one 

 which agree in every respect with Carruthers's species except that they show 



