GRAPTOLITES OF NEW YORK, PART 2 200, 



same laree rhabdosome that greatly changed in thickness from the base to 

 the last extreme branches. 



Hall describes his species T. capillar is without any intention of 

 identifying it with Em nous's N e m a g raptus c ap i 1 1 a r i s. The latter 

 species, however, is, in the writer's conviction — founded on the study of 

 typical material from Stockport which Gurley had identified with Nema- 

 g r a p t n s c a p i 1 1 a r i s — ■ based on drifted terminal fragments of the rhab- 

 dosomss which on account of their great delicateness have become rolled 

 up, and retaining but the basal portions of a few of their branches have 

 acquired an entirely different aspect [see text fig. 113]. The specimen 

 [pi. 10, fig. 7] could be readily imagined to become reduced to the form of 

 figure 1 13. 



The Rastriteslike aspect of the secondary branches [see pi. 10, fig. 6, 7] 

 is due to the regular breaking off of the extremely thin branches of the 

 third order at a certain uniform distance from their bases. The fact of this 

 frequent equidistant breaking off of the finer branches seems to indicate a 

 jointed structure which again is suggestive of their composition of thecae ; 

 but the latter could not be made out. Where these finer branches are pre- 

 served, the rhabdosome is wrapped in a hairy mass [see pi. 10, fig. 5, 8] of 

 such density that it mostly defies the discerning of the coarser branches. 

 These amazingly dense masses of fibers are frequently also drifted into 

 spiral masses as "Nemagraptus capillaris." "T. typus" and 

 " T . capillaris" are hence only the skeletons of more complex 

 structures. 



The main stipes and branches derive their greater coarseness not from 

 a composition of many thecal tubes such as is found in Dendrograptus, 

 Dictyonema and Inocaulis but from the deposition of secondary strengthen- 

 ing layers. In stipes broken through the center the original thin stipe 

 (" T . capillaris") is still preserved as a narrow canal [see pi. 1 2, fig. 14, 

 1 S, 16] from which the branches diverge at right angles. The thick wall 

 shows its origin in fine longitudinal growth lines. The apertures of the 



