686 NEW YORK STATE MUSEUM 



Position and localities. Rare in graptolite bed 2 (Tetragiaptus zone) ; 

 associated on slabs with Tetragraptus fruticosus, T. similis, T. 

 pygmaeus and Dichograptus octobrachiatus. The authors of 

 the variety report it from the Upper Skiddaw slates of Outerside in the Lake 

 district of North England. 



RemavTcs. I have hesitated for some time to identify my material with 

 the variety from the Skiddaw slates, for the reason that the latter has thus far 



Fig. 83 Didy mograpt us nicholsoni Lapw. rar. planus E. & W. Proximal portion 

 of rhabdosome. Keverse view. Deep kill. x4 



been found in a higher horizon ; but I have failed to find any important dis- 

 tinguishing characters, and the branches and thecae appear to agree with the 

 British types in all details. The somewhat smaller figures for the size of the 

 sicula in our material may be due to an incomplete preservation of the apical 

 end. The branches appear to originate in our specimens \see figure 81] very 

 close to the apex of the sicula and diverge from the latter suborally. 



Didymograptus filiformis Tidlberg 



Plate 14, figures 8-14 



Didy mograptus f ilif ormi s Tullberg. Geol. Foren. Stockh. Forh. 1880. 5:42, 



pl.2, fig.8-11 

 Didy mograptus filiformis Lapworth. Ann. and Mag. Nat. Hist. ser. 5. 1880. 



6:20 

 Di d y mograpt u 8 f ilif or mis Brogger. Die sil. Etagen 2 and 3. 1882. p.39 

 Didymograptus filiformis Tullberg. Sver. Geol. Und. 1882. Afh. och 



upps. ser.C, no. 50. p.22 

 Didymograptus filiformis Tomquist. Lunds Univ. Arsskrift, Bd 37, Af 2. 



nr. 5. 1901. pl.3, fig.6-9 

 Didymograptus of. filiformis EUes & Wood. Monogr. Brit. Grapt. pt 1. 



Pal. Soc. 1901. p.32, fig.20 

 Didy mograptus filiformis Ruedemann. N. Y. State Paleontol. An. Rep't. 



1902. p.556 



